The best thing I've found for long/all day sits in the cold are the ThermaCareback warmers designed for low back pain. I put it on over my UA layer once I'm settled into the stand and I'm toasty as long as it is. It keeps the kidneys warm and I think that is the key. The other thing you can use is one of the ThermaCare neck warmer for neck pain. Keeping your neck warm is also very important. Doing this will help cut down the layers and you'll be comfortable without all the shivering.