You're obviously WAY faster than just about all of us but it is interesting what you do with that right hand...almost like a mini-scull when you start your stroke. Idk, maybe you're searching for the best purchase on the water. You're also crossing it under your body when you flip...I wonder if a straight pull at that point would help you flip faster.
Anyway, the only way I know to make changes (if you're serious about it) is to slow things down so you can focus on it. Get the kick board out and do some one-arm work so you can watch what you're doing. Swimming with a snorkel would accomplish the same thing. You've obviously put in a lot of yards so tweaking your stroke won't happen overnight.
No matter how good you get there's always something to work on...that's what keeps it interesting.