I think having a second layer only on one half would be trickier to quilt. I'd also suggest a wool bat--they "breathe" which allows the body heat moisture to wick away and you stay warmer, which DH does feel sweaty. Plus they are very drapeable and not super heavy like a double batted quilt.
We use a wool bat quilt in the winter and I keep a lap quilt available during the really cold nights for DH (who gets colder than I do).