Replying to Spinning stance, wide?

Hey all, I got a pretty newbie question to suit my newbie-ness. I just started skiing park 2 weeks ago and can do some rails and boxes, spin 180 just about anywhere, and can butter a 360. But when I tried to spin a 360 off a jump in the park, I would spin til about 300. I haven't been back to try again much, though I did realize you're supposed to spin your skis midair at about 180 aerial. Anyway, so when I watch all these people throwing their 3s I always see them widen their stance before they pop, but when I tried that it didn't make me spin as fast. I'm guessing its all about centrifical (spelling?) Force and stuff but I didn't feel it help me at all.. someone said to maybe try popping off an edge? Idk but any help would be so greatly appreciated! I got pretty far I felt in the little time I tried park and now I hit a problem >.< Thanks again for the help!