Always found that the most import thing for me was to keep dry. Found that out for sure one summer in college when I worked third shift production in an ice plant - handling 8 and 25 lb bags of ice for 8 hours in a 35-40 degree room. I hated the gloves they gave us - they didn't fit and they held the water, so I didn't wear them. As long as I kept dry, had no problems.
I like the idea of wearing surgical gloves over fingerless glove for winter fishing. hands warm, fingers free, and dry. I'd probably change out the surgical glove periodically, cause they don't insulate that well and wet surgical glove can chill your extremities too, but if the base fingerless glove stays dry, that's an improvement.
TjD