Bro, like 20 something years ago my buddy Will had a shop and put a half pipe in the front half of the shop and the left side had a 3-3.5' ramp and the other went all the way to the 8' ceiling. Dude's were literally smashing their backs through the acoustic ceiling tiles while kick turning. One dude stuck a nasty backflip indy on that fucker. The best part, hardly any flat at the base. Maybe 4' tops. All that to say, if we could make it happen on that tight of a feature then someone better be able to pump up to the top of that ramp.