K3
Try to see why you're getting a tailing loop---maybe you aren't letting the back cast straighten out because the fly has so much air resistance that it goes slow in the air. Possibly you are trying to cast hard right off the backcast without stroking and accelerating. With a fly that big, you should need a double haul to get things going. Th first thing i would do is get the bigger rod out---the 6" long, bushy musky flies that i tied needed a 12 wt to get some control of the situation.
Its hard to tell without seeing whats going on.
Mike
"She had hooks to make a fish think twice!" ---Chris Smither-"Lola"