I measure in at bang on 6.5 (maybe a bit under before I started lifting and generally eating more) and would definitely classify myself as a skinny.
I was worried a 40mm Rollie would be too big but having received a 16610, it's perfect. Literally the perfect proportion, perhaps maybe even a teeny weeny bit on the small side, but I can see why the bigger guys definitely say Subs are too small for them.
I thought an earlier vintage 37.5/38mm would be perfect for me initially, but honestly have started thinking they could look somewhat feminine in their size. Don't get me wrong, I L O V E the small sleek watch look, which is why I was worried, but the 40mm just seems absolutely bang on the money for a men's watch.