single leg sit out finish to truck/twister

here's an attempt from my bro to get to twister from one of his favorite single finishes (the sit out).

almost there, i feel like we need to slap a lockdown during the roll.

here's the vid (1st version):
https://www.youtube.com/watch?v=TwdIJzgU7_c

here's the explanation of his single leg sit out finish:

https://www.youtube.com/watch?v=Ox5BRM1iejg

what do you guys think? onto something here?

as long as your opponent doesn't know what you are doing i would say it could be legit but otherwise it is very easily countered/flipped

Does this move rely on them giving you their foot? Is that a common reaction?

Dan henderson used to shoot and pull guard on a fail I believe, same idea.