Danno,

I spent 41 hours on a 20' catamaran in 6 days sailing up the eastern coast in the Tybee 500 earlier this year. About 70% of this time, I spent in the trapeze and the other 30% on the trampoline. I do have a bad back and it did get to bother me some early into the event and after numerous consecutive hours in the trapeze my rump was numb and painfull. However, you'll find that the flexible trampoline provides pretty good support and for the 'normal' 30 minutes or so you spend in the trapeze that it's all quite comfortable.

You sound like you are also hinting about wings. In lightish air, you wouldn't be able to use the wings either but in the moderate stuff, when you can use them, they're very very comfortable. Secondly, when the wind is even stronger, they allow you to trapeze Waaaaaaay out there off the wing for more leverage. The downside is that they will drag in the water if you fly a hull too high (and not very high at all).