I had these all lined up on the table and noticed the variation in case designs from Seiko - all in a fairly short period — I would say the decade of the Seventies.
I reverse the straps on watches that slide around on my wrist. Since watch cases have different shapes, straps have different lengths and friction against the skin, some tend to move and some don’t. I change straps and/or orientation for the best comfort.
With bracelets I usually can adjust the number of links on each side for optimal fit.