Re: brushy mountain inner cover?
When I ran it upside down, my bees sure did draw burr comb on it. I couldn't figure out what was wrong until I placed it back the way it's marked. My bees used the top entrance, however, when it was aligned with the 'this side up' facing up, too. So unless you just have a preference for how the dado is arranged, the bees seem to prefer it just the way it is marked.
Running screened inner covers right now above hive top feeders. It would have been nice if someone had mentioned to me when I was first starting that the inner covers with an entrance sitting above the hive top feeder was inviting robbers. But it worked great in spring when we had a flow-- the bees would take feed from the feeder, fly out, and go back in the bottom entrance with it instead of run through the other brood nest boxes.
I'm using Imirie shims for top entrances and just letting them burr the shim, honey supers, and queen excluders together as a part of their nest. I just take the whole thing off as one piece. I tried just using builder's shim for top entrances, but the huge entrances these created sparked robbing when no flow was on.
Maybe next year I'll start a hive that way and they'll have it all figured out before the dearths hit.
2 hives of Russians. 32 stings. 1 season of experience. And you-- yeah, you right there-- you're my mentor. XD