Thanks to everyone for the suggestions on keeping the hands and thumbs warm. I looked them all over carefully and began researching based on what you said.

I'm going with the Kolpin set-up sold by Amazon which has three parts.
1- Gear protector mitts. (Stay on the quad and block wind)
2-Hot thermal grips. (12V grip heaters)
3-Thumb warmer kit (With on/off switch)

The original plan was a pair of gloves/mittens that would do the job, this seems much more appropriate.
Thanks all!

My package arrived, and I installed the grip heaters, thumb warmer, and have the "mittens" (gear protector mitts) in my rear storage box at the ready.

I'm very pleased with the function of all three components, and I'm confident that numb digits are a thing in the past. I wanted to let you guys that were such a big help know it's complete, and your input is greatly appreciated.

Thanks again.

You will love them. I usually just wear thin gloves and sometimes I have to turn the temp. setting down.