I've done the airbag at buck hill, it's alright. Personally I think there is too much of a step-down to it which makes landing quite a big harder. Don't try to stick the landing, that hurts. Just let yourself fall. The airbag is really just to let you feel what the trick is like in the air and how to bring it to your feet from there. It shouldn't have much of an effect on when you take it to the park. My biggest piece of advice: POP. You will not do it your first few times and that's what you have to get dialed in on the bag jump. Once you do that and feel good about it, take it to a jump and you'll stick it to your feet first try. My friend Drew Olson (who skis buck mostly) has gotten a ton of off axis tricks as a result of that bag jump.
In this vid I definitely set to early because the bag jump buck does is scarier than it should be, and my friend just got concussed from it.
http://instagram.com/p/l5uGVMx-__/