Indra's Forme Tarck project

Your legs were dead straight though, with no bend at all

Did you see the angle of Henry's legs on the slave ride at full extension? They were by no means straight, and he has a custom frame!

Sumo?
He was on the makino.

Makino is set up to have the same leg extension as my Oak.
The baseline is 10 degrees of knee bend when at the bottom of your pedal stroke but it's a bit different for everyone. Since getting a bike fit and lowering my saddle, if I now put it slightly too high then my hamstrings start to hurt and I can really feel the power difference. Of course it also depends on the angle you like to have your feet at too.