BigA:

I split the Driftless into two seasons: Early season, I fish a 9' 5-weight or 8.5' 4-weight. I figure the chances are good I'm going to wind up nymphing much of the day, so I think the length more appropriate. On the streams I usually fish, casts are pretty much straight up stream -both dry fly and nymph - not much need for mending.

Late June through the end of the season, I pretty much begin to go small with 7.5' or 7' four-weights. Terrestrial season has started big time and I rarely have a nymph on my tippet. Not much going on with mayflies until September's brood of BWO's anyway; Epherons are burrowers. The likelihood of needing something to nymph with is pretty small. I also think you'd want something with a fuller flex, sometimes you'll be casting just a leader and maybe a foot or two of line.

I've found two exceptions to this: 1) If it's been raining recently, think about using a San Juan worm. Generations of farm boys have been fishing worms after rains. Why not us FIBs? 2) In late June - if the Hexes are still going, a big nymph could be ticket - particularly if the water isn't very clear.

My next rod is going to be a Superfine Touch 7' 4wt. I've broken my 4wt 7' boo so many times, enough is enough.