Barry, I normally use either my 6 or my 8 for these flies, especially in the larger lengths. However, recently I have been tying what amounts to a wooly bugger with rabbit fur inplace of marabou. Short 1/2" fur tail, then tie the body as I would a bugger. This is easily castable with my 4wt.
I cast the heavier fur flies the same way I do heavier clousers. Slow down my casting stroke, and open up my loops a bit. I don’t worry much about how the fly hits the water, as long as I put it near the structure aimed at.
This will solve your problem. Tie, or acquire some purple Hard-Hackle Worms in 6" and 8" sizes, tie one on and HANG ON! I’ve never come back empty (of course, I seldom do anyway) when using these. After you cast, let it sit for a moment or two (this is where some of the most explosive strikes occur). It will float and resemble a small snake. After about 30 seconds, give it a gentle twitch, and it will slowly sink and move sensuously through the water like a small snake or a large worm. Keep twitching it slowly every few seconds, taking in line as you go. This is the fly-rod version of a plastic worm, and it is deadly. The pattern is in the Fly Archives. It is easy to tie and the materials are cheap and readily available.
Good Luck!
[This message has been edited by Gigmaster (edited 14 June 2006).]
[This message has been edited by Gigmaster (edited 14 June 2006).]