I'm no carpenter but decided this weekend I could make a smaller box for my sugar syrup containers (the gallon baggies). The height of the box is about 3-1/2" and that gives plenty of room for the bees to move around and eliminates all that dead air space. It sure has been mighty cold so I added duct tape (the cure all for everything) to close up that crack a little.
And I added duct tape to the front of Hive #1 - a little gap there and I felt the need to help the girls a little.