I'm withholding final judgement until I see pictures with the ISO rubber, which is about the thickest rubber strap you can get as I understand. The main reason I sold my BS was the only strap that looked right (to me), and hid the gap was a Nato. I also like to have a rubber option with dive watches. Not a fan leather straps anyway, and it's not very useful on a diver imo.
is not about thickness... actually the iso has the holes very close to the ends, the gap will be noticed even more