Hi John,
I've done LOTS of cold weather riding in the past. In addition, I live in Colorado Springs and don't own a car.....my Savage is my "daily rider." I've run errands around here with temps in the single digits F. I've also, in the past, ridden entire days where it never got warmer than 25 degrees F. A few years back, I rode over 100 miles in single digit F temps.
Note that I've never owned or used grip heaters, so I cannot comment on them.
Having said all that, here's what I would recommend:
First, get you some hand deflectors to keep the wind off. Here's what I use in the winter around here:

They are fabric rip-offs of Craig Vetter's Hippo Hands that I picked up at a garage sale. I think these ones were made for use with ATVs. They work to keep the majority of the wind blast off of my hands.
Then, invest in a decent pair of electric gloves. I've been using Widder 'Lectric gloves for years, but the company has since gone out of business. I really haven't kept up with the latest, but I know that Gerber gloves work well. They are quite dear, but carry a lifetime warranty (AFAICR). In my experience, nothing, but NOTHING beats electric clothing.....
Lastly, keep the electric gloves in a heated area until you are ready to put them on. That way, they'll be warm when you put them on and will stay that way....