So what I did last winter - which was, to be honest, not a typical winter - was to use a solid bottom board. I had two deeps for the colony, then the inner cover, then a third deep (but with no frames in it). I left the inner cover opening a bit open but packed some insulation around it so that moisture could escape, while hopefully maintaining the colony's warmth. Put the telescoping cover over top and wrapped all three boxes with tar paper and put a mouse guard over the front entrance. I don't think I even reduced the entrance at all. Whatever it was, it worked - but as I said, last winter was not at all our typical cold winter.
So let's say I stuff insulation into the space under the sliding drawer in the screened bottom board to keep the cold out from underneath. All else will be the same: wrap the hive, insulate over the inner cover, keep an opening in the inner cover, no upper entrance. I'm just trying to avoid having to replace the bottom board, that's all. I'm being lazy (I know).
I don't like this whole winter business. It's stupid and a pain.