The first one you corked to late and it looked like you were going for cork 9 and the other 2 you were corking to early. Nice attempts though your really close.
dont throw straight backwards like in the last 2 cuz then you go to inverted. pop off and set the cork with your shoulders out, then tuck in. itll help you get a better axis and as long as you tuck and spot your landings you'll get it around fine
if u do them on a trampoline, add some ankle weights, it helps to get a feeling of something heavy being strapped onto your legs (skiis) when on snow. But sick attemps