I built alot of different style nuc boxes last spring. I used two basic styles, a single five frame stand alone, and a two five frame nuc in a standred deep body. The single five frame I put a solid bottom on, the double I put a full sbb (actually, I stapled the screen onto the bottom, and then placed cleats on to set it up off the ground). Both worked well. But the sbb double nuc did much better over the single. I orginally built two seperate migiatory covers, one for each side, then I also tried one big cover that covered both sides. I didn't place in the canvas inner covers as MB suggested. Keep in mind these covers just sat on top of the box. I didn't have any real problems with bees spilling over while inspecting them. But in retrospect, I was proably just lucky, and canvas inner covers are a good idea. Based on my experiments last summer, installing follower boards, if done properly, should work. Having a groove for them to slide in would be nice, be at times is just not doable. I would suggest putting screening on the bottom, stapled to the follower board, and having added cleats to hold it off the ground, I also had hive stands to set these on. If you use inner canvas covers as MB suggests, then you could even use the regular telescoping cover. Just some thoughts, sorry so long winded.
"I reject your reality, and substitute my own." Adam Savage