
I notice many of us here are very concerned about the size of 5100. As a lucky owner of this reference I confirm that the lug to lug length of this particular reference is 46mm.
And for comparison purpose I took a photo of 5100 alongside with other watches in my humble collection including (from left to right) GS SBGW 255 (37.3mm), Jaquet Droz Grande Seconde (39mm) and Lange 1 Small (36mm).
Of course a shaped watch wears and behaves quite differently to a round watch. But I hope you could have a better picture about the objective size of this lovely 5100 reference.
May I also take the chance to wish you all a happy and better 2021! Cheers!
Nig