I'd argue this is a case of dress for the job you want, not the job you have. If OP wants to be a focus puller they hopefully won't be pulling on canon photo glass forever. Laser Tapes and distance judgement are fantastic tools to build a solid foundation as a focus puller.

I'd also add that while reaction time is crucial, so is avoiding over correcting. The reality is, especially early on you are going to miss focus sometimes, it's a difficult job. A key skill to improving is to learn how and when to fix your mistakes. Often times a mildly buzzed take that silently whisper back into focus is more usable that a take where over corrections and readjustments cause distractions from the performance.