>I was able to get our varroa screens on today with the help of my son, but realized too late that I didn't want to trap the hundred or so bees under the screen by shutting off the old hive entrance.
I'm having trouble picturing what your intentions are and what your Screened Bottom Board looks like or if it's a "guy's insert" or what. Are these commercial Screened Bottom Boards? I've never seen one where there wasn't an entrance. I closed all mine off, but that was with the tray in and a top entrnace.
> Thinking that later would be better, I came back to the hive in the afternoon, where I find that now instead of hundred, it is more like a thousand in that small space where the mites are beginning to drop.....
How are they trapped here? I don't understand why there isn't still an entrance where you always had the entrnace. But if some are confused and are under the screen, you can put the tray in. If they are trapped between the tray and the screen you can remove the tray.
>So now what do I do? go through the whole process again and this time brush them all out, or wait until they vacate the premises or will they keep using that space forever?
They shouldn't be in that space. You should still have an entrance where there was always an entrance. If you have that there should be no significant nubmer of bees on the bottom. If there are put a tray in. If you don't have a tray, make one out of cardboard.
Does this set on top of the old bottom board? Does it make the entrance on the opposite side? If it does then you need to turn the bottom baord 180 degrees so the new entrance faces the same direction as the old entrance. With some screens this means that the old bottom board is facint the opposite direction with the intent that you can slip a sticky board under the screen.
If you're trying to move to a top entrance, I would not do that at the same time as converting to a SBB. I'd close the regular bottom board off first and when they are using the top entrance, then put the SBB on.