@CaptCalvin - I don't have a spare movement on hand, I was looking at buying a 25 jewel out of a Montblanc Meisterstuck which seem to be plentiful and relatively cheap. Here is an example with some photos.
@Bauertime - I will do some reading on addressing the hairspring, if it's a single part that needs to be addressed I can give it a go, but the watch has unknown service history so I'm not sure how worn the remainder of the movement is.
@bjd1020 - Thanks for the help! Yes, the concern is the blank space in the day slot. Is there a great deal of variance in movement sizes between 7750s that lack additional complications?