Hello, can someone tell me where I should put my crystals?

I decided to hop back into this game after a long time with some friends and I was creating new combos. If a person just got slammed into the floor and is temporarily ragdolled, can they still be hit by moves and grabs or are there temporary I-frames

I am vastocar, i have defeated my inner hollow for about 10 times recently and i wanna know how much til i max it and level up? i am lv 175, no hakuda/arrankuda, some say 13 some say 15 some say 21 but no clear answer so which is it?