No problem for me. Padgett describes the correct hand position as picking up a 5 gallon bucket of water. Your hand is stretched but in control without a death grip. I switched in late May and have dealt with mid-20's degree temps the past week in the woods without an issue.

 

I used to have a shooting pain or nerve issue for a while. It went away though. More due to carpal tunnel and arthritis than anything else

 

You may have to build up the right hand muscles, but shooting practice will take care of that, the fingers will hold some weight during the draw.

 

I've shot thumb and hinge for about 12 years and never had a problem with cramps. You want the back of your release hand flat with just the fingers hooked to hold the release. You want as little tension in the hand as possible. One technique for shooting hand held releases is to relax the forefinger to let the release rotate.

If you get cramps, you are doing something wrong or your release doesn't fit your hand.

 

Muscle cramps are not a result of what release you use but rather a result of hydration and electrolyte levels in the blood. Keep properly hydrated and you'll be fine.

 

if you're getting hand cramps it's likely due to tension in the release hand....keep it relaxed through the draw/release process and you don't have a problem.