Hi, Jim, glad to see you back!

If I were sitting still on a snowmobile, I'd wear what you are wearing. When I lived in Vermont (1960s), I wore every warm item I owned for iceboating on Lake Champlain (IMHO, the ultimate winter sport, but another one involving sitting still in cold wind). Back in my active days, I wore thin breathable layers so I wouldn't sweat while hiking or skiing but took plenty of warm layers in my pack so I could pile them on for warmth when I stopped for rest, lunch, etc.

Nowadays my "hiking" is limited to around the block with a walker, so the extra layers get to stay home. Plus the walker, not having skis or chains, is impossible to manage in snow. I also have to avoid falls at all costs, so when it snows I stay inside and enjoy it through the window. Old age catches up eventually!