Finger tricks tips ?

Hi, I got myself the super rs3m maglev ballcore and it pisses me off because the cube always slips off my hands (especially with D moves) I tried different configurations with the little purple thing + the screw but it doesn’t turn well anyways)

Do i aply way to much force when turning ? The cube also hapens to stuck REALLY often, maybe the cube is too thigh, idk.

Should I practice freestyle fingertricks for like 10 minutes or should I just try to turn it slowly ?

Regardless of everything I said earlier, can someone also tell me how to hold the cube ? I also forgot to share a pretty much important information : i have big hands. And i think this have a big impact (for exemple I struggle to put my major on the middle layer on the B side)

Thanks to anyone who will read this bunch of nonsense but yeah, I often struggle to express myself, sorry for that. Thank you all