I stopped by Cycle Gear but they didn't have anything in stock. RevZilla is close but I'll never give them another penny after an experience last year getting absolutely terrible (and outright hostile) customer service. I went to Cycle Gear afterward and they were super friendly and helpful for what we needed (I got some maintenance stuff, but we spent a fair bit getting a helmet and gear for a new rider friend).
In any event, I ordered FirstGear heated gloves, controller, and Y cable shipped to me. I finally got a chance to try them on now that I'm done shoveling snow for the week, and I'm very disappointed in the fit. The left and right gloves are literally two different sizes though both marked large. Left feels like a large in most brands and fits me well enough for a winter glove, but the right glove is clearly smaller in the finger length. I'm guessing a production mishap that got past QC. Bummer, I hooked them to a battery and they feel heavenly (in a 60* garage anyway). I'll give a shot at trying for consistently sized replacements. Bummer, I was looking forward to heated gloves for my Monday morning below freezing ride to work after the snow melts this weekend. In what I've read, Gerbing quality and customer support is not what it used to be. There is little info on FirstGear though it seemed mostly positive.
If round 2 with these gloves works out they are 15 watts each. I figure 30w might work with the 225w CB750 alternator, plus solid state regulator and clean wiring. Might have to replace the bullets on the stator wiring with blades as they tend to need a slight crimp to tighten them up periodically. I have a Cibie H4 reflector on all my bikes, huge improvement so I can probably go down to a 35w bulb and be better than a sealed beam. I do have a CB750A alternator collecting dust somewhere, those are supposedly 285w. I was planning to use that on my restored K1 next time it's apart but it may make more sense to use on the daily rider K5.