Replying to 270 on help

i can 270 pretty well but most of the time my rotation keeps going (revert 90 to straight)

and then i just 180 off

recently i have been trying to keep my upper body from facing end of rail (to stop rotation)

and i usually dont get centered on rail when i try this

also

i cannot seem to do the scissor? how do i help myself learn to scissor that way cuz i can scissor the other way perfectly