I think you will be fine with a 6.5in wrist. My wrist is 16cm/6.3in and I think it looks ok. Here is a picture I took about 12 days ago. I know not the best but I can take some better ones if it helps?Such a beautiful watch. Is the Lug to lug actually 51mm from pin to pin or is that tip to tip? I'm just slightly nervous due to having 6.5in wrists. 51mm lug to lug is long for little wrists like mine.