66, You are on the right track and are thinking about all of the right things. Using multiple layers of gloves helps compared to one big thick pair. I use lobster mittens, (fingers are in two pairs of two instead of one big clumsy mitten. Gaiters from your cross country ski kit sure help keep that wind from roaring up toward the crotch. I usually don't need a balaclava, but do use a chin scarf to seal that junction between my helmet and my jacket. Your handguards look great but hands will always be the coldest and most critical weakness (think clumsy equals unsafe). I believe the atv wind deflectors in front of your homemade ones (or my Moose Racing guards) help even more, but they do make mittens that fit on your bars and you stick your hands into them. I'll try to post the addon atv winter guards.
Here they are from the back. They did not interfere with controls and stayed in place, but did deflect even more wind from the hands.
I also find that carrying a totally different set of gloves helps because I can change from one setup to the others and get the benefit of added circulation in different places.
Ride safely and wave as you go by. Oh by the way, there is one other trick we practice in New Mexico - wait until 10:00 or so when the temp has risen 20 or so degrees from what it was at 0800. Cheers, Tom