One thing I have found that helps me is to extend my legs straight. The footrest on the hang on I put my legs (heels) on top of it to straighten my legs. I also blouse my pants and pull them loose in the thighs siting down. This helps to keep the legs warmer and better blood flow and the feet stay warmer for me. Hunting on the ground in the turkey chair for deer and my feet stay warmer.
Sorry, still can't help on the boots.