Not crazy at all...until you hook one...
The saving grace in casting heavy Musky flies is that you generally don't need to cast far, accurate, but not that far, at least for the structure I fish. (weed pockets, deadfalls, edges of weed beds, shoals etc) You can actually get pretty close without spooking them. I rarely cast more than 40'. Keep your loops wide and slow the stroke down a bit.
All the flies mentioned will work. A large all purple or all white wooly bugger is a pretty consistant fly. To make them long (6-8") you can use two hooks. The front is all body (I use marabou wrapped around the shank vs chenille to keep the weight/wind resistance down), and the back is half body and tail. The jointed body gives a nice wiggle when strpped and stopped. Other good combos are red/white, yellow red and yellow black. I'm sure other colours will work.
Good Luck, Let us know how you make out.

Chad.