Recently acquired a 40" x 52" underquilt and it fits well as a down cape, as a substitute for a down vest.
Tie all four corners together in front and do something to clip it together under your chin. At my height, the 40" in back covers from butt to over my shoulders, and my arms folded in front put them under the overhang there. The way the bunched up fabric bows out, makes a place for my elbows to be covered. Sitting down in my hammock, typical cooking position for me, there is full torso coverage. A shorter length UQ might not fit as well.
I'm wary of cooking while wearing my top quilt so this is good news for me.
The bad news is the UQ still weighs more than a vest, but dual purpose helps there.