I have the Stubben NT MONO stirrup leathers that are single thickness at the bar/under the leg, adjust at the bottom with a conway buckle.
Love the feel, and they have been very hard wearing over the years but they are a PAIN to adjust and don’t go short enough for my trainer (making extra holes in them is something I’d like to avoid as they have a web core and punching through will probably make a mess…)
They are also not possible to run up, so I cross them over the seat resulting in bumps and scratches from the stirrups.
I like the Bates webbers - are there any other innovations in the field that people like?