Nice shots and all but the part that matters you can't see :<0)

Linen and leather are 2 different things. Linen generally goes first to remove dirt from the blade and do most of the heavy lifting of stropping. I wash my linen when it gets dirty and way more often than my leather.

Another experiment you could do is stropping on different kinds of leather. Progressive stropping. You may not be able to see a difference but you MAY be able to feel the difference. Once again it's not what you see but what you feel.