Steep lip, 5-6ft of air. MAKE SURE YOU COMMIT! Its not a tough trick, try practicing gainers (forward moving backflips) on a diving board. All summer I did this and when it came time to huck a back it was really easy, almost no fear. Also, when in the air, if you can remember this, extend your legs if you are rotating too fast, pull them in all compact like if you need to speed up. I still seem to over-rotate on big tables, I think I just freak when Im upside down so high and tuck, oh well at least you know what to do if you can control your fears. Thats standard backflip advice in a nutshell, actually its pretty thorough, but the key to the trick is commitance. Once you huck it youll be wondering why you havent tried it earlier. Good luck.
'Computer games don't affect kids; I mean if Pac-Man affected us as kids, we'd all be running around in darkened rooms, munching magic pills and listening to repetitive electronic music.' -Kristian Wilson, Nintendo, Inc, 1989