A bit stiff at first, but then takes on a comfy shape with wear. Modest 2mm taper, I believe. My 20mm happens to be off watch right now.
I'll note that the underside takes on small ridges. Doesn't bother me...actually helps air things out, as with a diver!
I believe @StephenRL has had the same strap on his Speedmaster lately, which looks great! If you go back to Tuesday's page 9086 of this thread, you'll see his.
My birth year Seamaster gets little wrist time. After moving through the entire month, from the 10th to the 6th trying to set the date on this non-quickset movement, I overshot in my COVID haze. I guess it’s the 7th now.
HAGDA!