Cockpit fit, coamings, knee braces are not a solved design problem by any standard.

I always raise the deck and the coaming about an inch and I've got average sized feet 8-1/2 and I'm 5'8"

I made a mock-up of the Mystery cockpit, and the only number I'm solid on is to tilt full-foot foot-braces 28 degrees off vertical.

Seems to me there should be a modern method where basic body measurements integrated with kayak width should quickly calculate into a clear basic set of
dimensions. It's a three dimensional problem that I haven't cracked.