The seat you use is an important factor, get comfy and you can play easier/better.
I made my own seat. A box with a padded top, compartments inside to fit "stuff" and a door in one side. I got the height by measuring from the floor to underside of my leg behind knee when sat down - the padded seat is bolted on top of that but, in use, it squashes down anyway so it doesn't add any height. That tallies exactly with keeping the knee joint bent at 90 degrees (as above) although I didn't think of it that way at the time. If you make one, don't use chipboard, I did and it's heavy! Ply on a frame is better - box in a wooden bar stool, cut to height!
My old Fender has 24in legs and the underside is at good height for my size and the box-seat. The KLs don't dig in, I can reach the vertical, and work the pedals with my heel on the deck. But my Mullen has 26in legs and my box-seat is short for the job, so the KLs meet me almost on their points - ouch! I had to get a keyboard bench to make the extra inches and my thighs now slope down from the seat, like somebody mentioned above, and the KLs are not so convenient. I can cope with this because I have "flags" on some of the KLs, so they have more "area" to catch with my knee without discomfort, but not ideal. The further the KLs are away from where you sit, the more important it is to have them comfy as those ones contact a more boney bit of leg.
Flags help a lot. On the Fender I have a couple of the outside KLs with bars (like flags) attached. The bars are fixed at 90 degrees to the KL and engage with my leg just below the knee. I'll try to picture that. OK, there's one - on the far KL, the photo's taken from the left end. It's quite comfortable in use.
here's a better one,
Good luck, Tony.
PS - Henry, I found drum seats (why do they call them "Thrones"; pretentious beggars) have a swiveling top and engaging KLs can send you spinning around, or at least losing some stabilizing effect and/or control?