This is my first season wintering in 8-frame singles. So far everything looks really good. I have a few in the field and a few in a cellar house.
I would agree that they seem to fill out the whole box, covering 6-7 frames of 7 total.
DD seem to spread upwards in Jan and Feb and occupy 3-4 frames in both boxes. Though they seem to use most of the feed in the lower box before moving up.
In my experience, open space in an 8-frame DD in the fall is bad news. They need all of the space filled with honey with a frame or so of brood. Otherwise they just don't have enough feed. Also make sure they have been plugged out of the upper story. Otherwise they move up too quickly and starve in Feb-March.
I have used most races of bees and they all seem to winter well in 8-frame, even Italians. Which are heading some of the singles this winter (MN Hyg. and Wootens.
"They would give a hive nothing but drone comb or nothing but worker comb. The end results were still the same."
If they had nothing but worker comb were did the drones come from?