just practice bru, and if youre running out of rail, use a a longer rail/kink rail/etc. Or just streamline the trick.
Since its 270 on, switch up, pretzel out (via frontside), its not too hard to stop the momentum, but since youve basically spung 450 by that point, its going to take some aggression. Work on using your lead foot to stop the momentum by grabbing the rail, while keeping your upper body facing more towards the end of the rail. That will help stop the mometum and set you up well to spin frontside 270+ out.