The ambient light makes it a lot easier to do projects, and even in mid-winter you often get moderate temps and sunny days when the air temp under the cover warms up enough to work for a few hours. I re-did all my winches last year in Jan-Feb and it was often quite pleasant under the cover.

I realize there may be reasons of protecting the woodwork from sunlight to consider.

This pic was taken yesterday. My covering system involves 2x3s hinged at the top. A PVC ridge pole connects them at the top. A pair of 2x10s, slotted for the shrouds, transverse the mast area. Forward of that I use PVC pipe tied to the spinnaker pole which angles down to the bow.

Max