Thanks for all the great advice. I think I will try the Sugoi arm warmers first - they are shorter and the lightweight fabric is better for this area (the coldest it gets where I live is 45F°). I will probably get the bolero eventually, but doubt I can master the on-bike removal.
I just pictured a scene where EMTs are finding my body/bike in the bushes next to the road, my feet still clipped in and my head/arms completely entwined in black fabric. Cause of death: Cycling clothes.