For the tantrum in order to grab I basically had to re-learn the trick. You have to square up more but also have to do more of a pop them bring you legs up and throw your head back. Right now I'm assuming you are throwing you head back off the top of the wake like most people do when learning this trick. When grabbing its more like leave wake, legs up, grab, then throw head back. Until I trusted myself to do this I was constantly chasing the grab.
I can't help on backroll. Mine is very "Mexican" and I can't seem to correct that lol
On the bs 1 key is wait, wait, wait. Throw it at the last second. I sometimes take off a little tail heavy, and after rotating that leaves the nose a little higher in the air so you shouldn't take as many nose diggers
Hope this helps some...