cazalea[Seiko Moderator]
20970
I think it depends on your wrist more than anything
The orientation of a long or short strap (half) depends on the way that the watch sits in the little valley between the bones on your wrist, and all the muscles underneath. With a bracelet and removable links you can move the deployant buckle back and forth underneath the wrist so the hinged parts sit properly and don't pinch or constrict your arm. With a strap that's a bit harder to do, as we don't all buy a new strap by specifying the lengths of either side. But you can adapt the location of the deployant by swapping the straps from top to bottom.
As other people have mentioned, this might make the buckle "upside down" for some people, but comfort in wearing is more important than the orientation of the logo (if any) underneath your wrist (in my opinion). So the watch strap might be mounted one way or the other depending on the watchmaker's intentions, forgetfulness, your specific wrist, or the instruction of the manufacturer.
It's safe to say "Your Strap May Vary" as long as you are happy with the fit.
I have both depending on the watch and lengths of the two halves (and the single or double deployant design)
Cheers,
Cazalea