How to calculte mosfet capacitors (Cgs Cds Cdg) knowing the charges Q
I realize that I am very late to the party but the question remains unanswered. 

Cgd = Crss

Cgs = Ciss - Crss

Cds = Coss - Crss

You'll need to pick the values at the operating conditions you are working at.

This video should give some ideas https://youtu.be/iATO3mUKBPc