I believe at 6’1” I max out my Hobie’s leg extension for the pedal drive.

At 6’10” I don’t think there is a pedal drive kayak that would fit Jon anywhere near comfortably. I think Jon (at best) would need a PADDLE kayak (at best). Those may not even be comfortable for leg room and foot rests that are far enough away…his feeey would be past the stern of the yak.