personally the jump needs to be at least 15feet for me to grab a spin otherwise my spins too slow,
You kinda just reach down and grab like right after you throw your spin, I learnt mutes first, and still mostly the only grab I do with spins along with the mute where you grab behind the heel dont know what its called
but ye I learnt off like a 20-25foot booter into fresh snow where your not afraid to hurt yourself and you just gotta go for it... got it down pretty good by like my 3rd attempt... first two my grabs were just pretty half ass... obviously I could do both the grab and 3's first
but ye just build a booter and go for it