My typical set up is a 3/8" entrance at the bottom, in winter I close it down to about 2 bees width. In the summer it is open 6 to 12 inches. i drill a hole just below the finger holds in the upper brood box, wide open in the summer, in the winter I close it to 1 bee width using cardboard so they can chew it more open or propolize it shut. Here in Montana that's all the ventilation they need. I do use quilt boxes over the feeding shims in the winter, they are very effective at removing moisture.Grins.
Have you found that they need any extra ventilation, such as a hole in the box? I have since done a few more, but I drilled a hole in the supers instead of the brood boxes to see how that works. I'm wondering if I will need to drill a hole in the top brood box when the supers come off.
Here in Ar., we are very humid, so I think the hole is necessary. Maybe Grins will share some insight as the UoG video didn't address dbl brood boxes or supers. I may need to go back for another listen if I can get my internet or computer issues solved. It has been hit or miss for a while.
^ i think this is key! healthy robust colony that has not been disturbed in the fall such that they can properly organize their winter nest. i started using reflectix last year with no upper entrance. no losses from those colonies and very strong coming out of winter. these hives were high enough to not have the entrance blocked by snow. this year i incorporated pallets and my singles on pallets have a 7/16" hole drilled in the handhold.I have never seen any damage caused by moisture to a healthy colony.