You cannot enter the heat into the equation due to the time of year and extreme difference in climate

between two extreme geographical locations.

You are correct, climate plays a significant factor in how we manage bees and what works best for each of us. It is often overlooked when responding to someone, mostly unintentionally as we just subconsciously think everyone lives the same as we do.

On average, the shape and the size of the brood cluster plus the unused space with in the hive body has as much if not more to do with the heat factor than what material the hive body is made from.

Likewise, this may be true in your area, but it is definitely not true here. If not for the heat, how can you explain a yard of 20 nucs with the queens all raised from the same mother queen and all mated in the same yard. 10 where polystyrene, and 10 where wood. 8 out of 10 polystyrene hives where significantly stronger than the wooden nucs and the remaining 2 where equally as strong as the strongest wood nucs.