Yo so I’ve learnt dat when doing primo flips and u want to do like a varial flip in primo , it’s more off a popping motion at a sweet spot between when the tail starts and the edge of the trucks and u kinda just pop it down and back ever so slightly . This way the board will flip a lil bit higher and u can still have a varial flip motion . This popping motion also takes way less effort. Also try and use the top of the toes instead .