Re: A deliberate chimney.
I am not clear on the thinking that smaller boxes are better for over wintering than larger ones. If the population of bees remains the same. The first thing I notice is that you have increased the outside surface of the colony by about 30% or so increasing the heat loss. I do understand the idea that the bees are kept on all frames better this way and don't tend to loose contact with the stored honey.
I would strap them down.
Significant Minority vs Insignificant Majority, 20% of causes produce 80% of the effects.