Paul watch this video. At the very begging Tenkara-no-Oni is doing what they call snake rolls. http://www.youtube.com/watch?v=zTld2_yAHO4&list=UL

Now If I understand your problem with long lines it is slack at the end of the retrieve? If this is the case You are trying to fish too much water with the long line. With a shorter line you can fish most of the line at still cast. With a longer line you can only fish a certain amount of line say 6 to 7 ft. Of course the lighter the fly being used the more area you can fish. Tenkara is still like western fly fishing when it comes to casting. You need to get the fly and line moving to make a cast. Easiest way is with a tight line. It may actually be easier if we fished together again so we can show each other what we are talking about.

Mike P.