I haven't really heard of shrinking hands... Well, them looking smaller because of muscle reduction, yes, but that's pretty much all.
Though foot growth, that would actually be more plausible than foot shrinkage. Bones shrinking is a pretty surprising, seemingly impossible phenomenon, but growth isn't. As a simple example, men's facial bones masculinise - which is growth - considerably due to testosterone during adult age.
And even some amount of "hand growth" would be absolutely possible - and even expected - from testosterone. I won't put this as rock-hard proof, but no matter the amount of physical work they do, the muscular character, the width, of men's hands that I've seen, have always been roughly proportional to their age.
Really, FTMs are a bad example to compare here. The changes we're discussing for MTFs are much less likely, much harder to explain, than what could happen in FTMs, who get much more significant effects all over from their HRT, in average.
