I hate webbers :/
No bulk under your thigh but with the webbers I bought to go with my jumping saddle the fastening is ALWAYS under my lower leg and gives me the most awful bruises.
I actually have cheap leather stirrup leathers on my [synthetic!] jumping saddle and I'm having no issues. I'm not a fan of synthetic leathers because the slimline ones are ugly, the not-slimline ones are too bulky, and the suede ones cost a fortune! I do have suede leathers on my dressage saddle [synthetic, full-suede] because anything else would damage my saddle but they came with a saddle that I bought a few years ago.