All of my hives are double deep with wooden inner covers & telescoping outer covers . I keep a stick of wood on the front of the inner cover which keeps the outer cover propped up for ventilation . I have never seen any bees coming or going out from under the front of the outer cover although there is plenty of room . Why wouldn't the bees use this space as a top entrance ? The outer covers doesn't fit all that tight & if they are slid all the way forward there is a gap between the hive body & the inside of the outer cover that the bees could easily get through if they wanted to . Also , could I cut a notch in the rim on top of the inner cover & get adequate ventilation without propping the outer covers up with sticks ?
My setup is similar....2 deeps and a medium super right now. I have the inner cover propped open with an entrance reducer, then a telescoping outer cover. I too have never seen any of my bees use this "upper entrance" even though it seems like they would.
--Steve