Personally, I think watch shape has a lot to do with it. Not just size. But I don't really care for overly huge watches generally. Maybe you'd get used to them though.
Ebel BTR (at 45mm) looks great but UPO (45mm) is just too big. It looked too big on me, and I'm 6'3 and 270 pounds. It's just clumsy and unbalanced... dunno how SA would look.
UPO protruded ugly on my wrist bone and the dial is too basic, plain. Not much going on there. That's why 42mm PO is much nicer.