This is a serious on going problem--especially yesterday after 23 nM--I could barely walk for about 10 minutes

Pegs are a concern I think I can contribute something from experience. I've got Sealine Smart Track pegs. My toes start cramping after a couple of hours.

First, I don't think pegs are nearly wide enough, I've also worked on step ladders with 3" wide steps--and after awhile my feet and toes began cramping.This suggests I need a full foot brace--or stiff soled shoes.

I never get feet or leg cramps walking around on the ground....

I find that the better and more fully engaged my paddle stroke gets the worse leg and foot cramping gets.

my calves also cramp. What comes to mind is Deep Vein Thrombosis--airline seat blood clot stroke disease. I've added an air camp pad underneath my gel pad that sits on my carved minicell pad, (no back brace)..... I'm probably contributing to the problem at this point.