Hahahaha nice ending!! Just from my point of view you got the spin down pretty well, and from everyone I've seen that has attempted a b-twist usually does too. All you have to do is lift more and you can definitely do some crazy swingthrough or something out of it!
I tried b-twists before, but I had to take a break from them for a while because I got some huge bruises on my knees from bailing them, even on a mat.....hurt like hell