I just dont get why tehy havent worked on it already. Unless there is a spacing issue with the current available Chinese movements
Looks to be the same (or at least, visually similar enough to the eye) spacing as the JLC Master Chrograph. There's already reps of those using the A7750 in a two subdial setup.
Thickness is usually an issue with 7750's as they usually hit the ~15mm mark (the Polaris Chrono is 11.9mm), but there's a couple of dual-subdial IWC Portugieser's using the 7750 that came out this year that are sitting at 12.5mm. It can be done, I just hope the factory thinks it's worth the effort.