How did you modify to get more clicks from the buckle. I'm at the very end and could sometimes use one more click.
The non-buckle side (the side with the notched strap) is sewn into the shoe. What I did was take the stitching out, cut the part of the shoe that wraps over the instep of the foot about 1/2" shorter, then sewed the strap back into the shoe. With an industrial machine that mod was easy. It may work with a more typical "home" machine. The machine needs to be powerful enough to sew through 2 layers of fabric and the plastic tab on the strap. I used a thread heavier than a "home" machine may handle however.
This is an example of the "sewable" part of that strap that's hidden between layers of fabric. This pic is a D-ring, but the flat tab is the same style.
The part of the shoe that rubs my inner ankle I may sew as well - my thought there is to fold over the offending area then throw a couple of stitches into that area to hold it out of the way.