>>[in stacked colonies for the winter] Close the escape hole, and moisture goes out the upper entrance. Then...add a second inner with the rim up and notch to the rear. This acts as the upper colony's bottom board and bottom entrance.

I run stacked nucs - 2 per a deep box => 4 per a 2 deep-stack - with corner entrances all facing south in the summer.  Any drifting seems negligible.

With a double colony stack with entrances facing in opposite directions, I would concerned with upper colony to the rear or north in winter.  Would the bees in those colonies be less inclined to take cleansing flights on semi-warm days since their entrance would in cold shade?  Or somewhat hypothermic bees returning to a cold entrance might collapse there and not make it inside.  Do you see any of this? 

Thank you.

Waldemar

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