Use what feels good. There is no "magical" shaft that can make up for an inconsistent stroke. Find what you like, and work on in proving your fundamentals! I can only speak for myself and I prefer 12.5mm.
luxury I think he means slight bottom left... as in a touch of outside. (i could be wrong)
great video, quality was excellent... and Coach reminds me of a Drill Instructor i had 12 years ago!
Thanks for the information.
Moose