Trying to transition from the back to the twister as a lot like going for the banana split in the wrestling world right? If you and your opponent both have big ass legs then yer gonna spend a lot of time trying to dig your foot into the inside of his leg. I would personally abandon that technique if you opponent isn't giving it up. There's a lot of other things you can do if you have his back. Not too keen on the jiu jitsu lingo but there's a video where eddie talks about doing some kind of hook on your opponents arm. He talks about attacking the right arm with your left arm in no gi world because you can't get good grip with the right without having the gi to grab onto. Totally blanking on what it's called though. And correct me if i'm wrong but isn't your opponents balance is going to become unstable if he's squeezing his knees together to block your foot? Or you could lock your hands into the bottom of his diaphram and squeeze at the same time dig your heels into his thighs kinda like you're going getting ready to launch yourself forward. Push his legs back with your heels and squeeze like son of a bitch with your hands, arch your back. If he's guarding the choke then he only way he can stop from being broken down is by posting with his hand which leaves him open or by pulling one of his legs forward to regain balance also leaving him open. Maybe i'm talkin out my ass here but i think that would work and critiques are welcome.