No less an authority than Dave Hughes recommends a DT one weight heavier than rod weight for 30 foot casts and dry flies.
Before I read Hughes’ advice, I bought a 5 wt. DT for a 5 wt., 9 ft. St. Croix Ultra Legend and was disappointed as the cast seemed to fade with a #12 Elk Hair Caddis or similar fly.
Would a 6wt. DT have been a better match for the rod?
Before I spend $60+ for a line I may not want to fish, I ask your advice.
I understand your problem with the price of line. There is alot of flyshops discounting Rio Selective Trout and SA Trout so they can make way for the Rio Selective Trout II and SA new line. I have seen it almost half off.
IMO, when selecting lines it can be tough. A rod will cast different with a DT and a WF. I have done some testing with a series of rods from a company. I was told that a WF is what it was based on. After taking the rods out, I found that DT worked better on 2 of the rods out of the series, while WF worked better.
What type of line are you using? If you are using a trout line, then you might want to go to a GPX. I believe that rod is a fast action so I would look at a line that is made for a fast action rod like the Rio Grand or Rio Gold.
This is only my opinion and it is to be used as a guide. If you know someone with a different line, I would ask them if you can try it on your rod.
Best Regards,
TS
Trout Staker is absolutely right, it really depends on the rod, as to whether it will cast a DT or WF better. A friend of mine uses a 3wt. DT on a Sage 0wt. TXL and it casts beautiful. It still makes those feather soft casts but will also handle some wind and a fair amount of distance. The best thing you can do is to try different lines and see what works best on the rod your using.
Before buying your next line for short 30 foot cast, look at the taper chart on the back of the box for both WF and DT. Many trout lines are all but identical for the first 28 feet. Also the above guidance about extra heavy lines is good to follow. Some rod makers mislabel their rods, what they call a 5 wt is actually a 5 1/3 or so weight. Determine if your’s is accurately labeled and try and appropriate line.
RoyC
While I think Trout Stalker gave you great advice; a #12 EWC is a tad on the air resistant side. Possibly your leader is a bit too long or the tippet is too light.
Just for the record; when I’m fishing short my leader is short too so the maximum amount of fly-line is past the tip top.
RoyC is correct the first 30" (approx,) of both WF & DT are pretty much the same. I would suggest adding a 7’ furled leader to help with that fade you mention.
I’ve been trying DT lines more as my casts are in the 30’ range in situations where you don’t have a lot of clearance for the backcast and I think they work better in these conditions.
I’m also a firm believer in furled leaders and own nothing else!
One other thing is remember the 3X rule and I believe in it. You take 3 and multiple it by tippet size and this will equal your hook size plus or minuis 2 hook sizes. 3 x 4 = size 12 elk hair.
At 30 feet, I could overline most of my rods by two or three line weights, and it would still work just fine. Underline em, too. Most good casters can compensate for lighter or heavier lines, big flies, etc without too much thought and varying degrees of effort, but some rods just need to be overlined to be comfortable casting for some people. No way a #12 EHC should bother a 5wt line.
HRC… you mention that the fly/cast tends to “fade” hummmm… to me this would be a funtion of line speed ,fly size, leader length and taper… lets not forget the size and length of your tippet.
Can you provide anymore info as to your setup so that we may help you?
Z
Z–Thanks for your response and in answering your question, I was using a 9ft. 4X leader with a #12 Elk hair caddis. From what I’ve read, I should be using a DT because it allows for a softer presentation of a dry fly, but the 5 wt. WF delivers the fly better.
So, what I’m trying to figure out is if a 5wt. DT (Orvis trout) on my 5 wt. rod is not the right match, but that a 6wt. DT would be better.
HCR:
You are reading too much. 
Since the first 30 feet of MOST double taper & weight forward lines are the same AND you are also casting 9 feet of leader; that means at 30 feet you will only be casting 21 feet of fly line out of the tip.
Bottom line; at 30 feet your presentation will not be effected if you choose a WF over a DT.
Now back to the over-lining thing. If you decide that over-lining will load the rod the way you want it to feel at 30 feet; be advised that IF you buy the next size larger fly-line and cast further than 30 feet; a DT will REALLY overload the rod since the belly is longer.
Take it from a die hard DT user; the dry fly presentation thing is REALLY overrated when you compare DT’s to WF’s making normal casts at normal ranges with normal flies.
I don’t do the over-lining thing since I have confidence in what the rod makers say the rod is rated for. I also don’t always cast 30 feet so I need the rod to respond accordingly. Bottom line; if the rod still doesn’t feel right at short distances it is usually just because the rod is too fast to have much soul at short distances which ISN’T a bad thing.
Rod action preference is the most subjective thing in fly fishing. It is just another example of how you can get into trouble by reading too much into what the “writers” say about tackle. Take your rod to the nearest fly shop a TRY some other lines. You will only be positive when you feel it for yourself.
HRC,
IMHO there is no real difference in short to very short casts between WF and DT - because - there is very little difference in the first 30 feet or so of line (Like JH says). Yes - overlining will make a rod load better and feel better on short casts - especially if you have one of the stiffer rods in your rated weight catagory. You should check the rod in Bill Hennemans “Common Sense” database to see where you are. Sorry Bill, I think I spelled your name wrong.
Very stiff rods on very short casts will respond to overlining nicely. Just don’t expect them to feel good at 70 feet. And don’t expect to cast as far at 70 feet with a DT line as with a WF line - unless you are using long distance casting techniques and need the extra weight.
Now I have to get my head down because there are a lot of other opinions out there and I expect some flak.
Bob
[QUOTE=Bobinmich;204190]HRC,
You should check the rod in Bill Hennemans “Common Sense” database to see where you are. Sorry Bill, I think I spelled your name wrong.
Thanks to you Bob, and to all others who have helped me here get some clarity on yet another mystery of fly casting.
Bob-where can I find the database that you refer to?
[SIZE=3]Here is a good website that goes into some detail about line types and weights and tippet/leader sizes.
http://www.dickssportinggoods.com/sm-fly-line-buyers-guide–bg-222872.html
Also, Wikipedia has a good write up about fly fishing, the history of, rods, lines, reels, flies, etc.
They also display the AFTMA chart for fly line weights.
http://en.wikipedia.org/wiki/Fly_line
?Many credit the first recorded use of an artificial fly to the RomanClaudius Aelianus near the end of the 2nd century. He described the practice of Macedonian anglers on the Astraeus River:
…they have planned a snare for the fish, and get the better of them by their fisherman’s craft. . . . They fasten red . . . wool round a hook, and fit on to the wool two feathers which grow under a cock’s wattles, and which in colour are like wax. Their rod is six feet long, and their line is the same length. Then they throw their snare, and the fish, attracted and maddened by the colour, comes straight at it, thinking from the pretty sight to gain a dainty mouthful; when, however, it opens its jaws, it is caught by the hook, and enjoys a bitter repast, a captive.
In his book Fishing from the Earliest Times, however, William Radcliff (1921) gave the credit to Martial (Marcus Valerius Martialis), born some two hundred years before Aelian, who wrote:
…Who has not seen the scarus rise, decoyed and killed by fraudful flies…
The last word, somewhat indistinct in the original, is either “mosco” (moss) or “musca” (fly) but catching fish with fraudulent moss seems unlikely.?
Larry 
[/SIZE]
Best database with Bill’s data in it I have seen is on SexyLoops. http://www.sexyloops.com/eric/database/rodtablesorted.php
You can also Google “Common Cents System” to get the methodology.
I think there is also a database on this website - ask JC or do a search. JC has written some responses to it and knows Bill.
IMHO - and I always have one - the most important number is ERN. The higher the ERN - the “stiffer” the rod. This is a gross oversimplification but it will allert you to the fact that not all 5 weights are really 5 weights. There is a parallel discussion of what rod stiffness is on my website www.HATofMichigan.org on the e-book page under “The Mechanics of Flycasting”. But beware, this is a slippery slope and you can get sucked into the geek world in a heart beat.
Bob
HRC,
In any aspect, DT or WF, I would suggest stepping it up to a 6wt line for your 5wt SCLU.
I have an 8 1/2ft 5wt SCLU Jacklin Rod, and it doesn’t respond well to any 5wt lines that I have tried on it. It’s just too fast. Not that this is a bad thing, (I love it so much that it has a thumb groove in the handle), but fast rods like this one need a heavier line to load properly.
Bob–I went to the sexyloops site you suggested and they have one heck of a lot of rods listed but none by St. Croix. I’ve searched for the “common sense” on FAOL site with no luck. Any suggestions? thanks.
HCR This might help.
mcsteff
There’s one St. Croix