(sorry for my english)
I Landed my first crows this week after 4 tries. It's easy compare to other tricks I tried! Once you got the crow or the front, your are suppose to stick the other because is the same start (toe side trip flip). The only difference on the front is you let your back hand go after the trip! I did the front after 5 tries yesterday and it felt good because it's very close to the crow! Two new tricks in two days.... felt good!!!
For the butt landing part, just try to be more patient to trip at the really top of the wake, be tall and don't throw yourself to much to the front. Waketrix.com for visual!!!