This is really brilliant. I've acquired a couple of ten frame ideal boxes and want to run all ideal frames, but also would like to try top bar style specifically for ease of access and lack of lifting while I'm learning.
When fitting a nuc into one of these would you put them in the middle, letting them expand side to side, with the entrance to the centre of the long side (coolwise?) or to the middle of the short end (warmwise?) with the bees at the front door end of the hive and expanding towards the rear?
Also, once full, would you then be able to add a section vertically, say an 8 frame super, or even a couple of them for honey flow?
There are different schools of thought, but most recommend that the hive start on one end instead of the middle. For clustering in the cold you want them to be on one end and work toward the stores on the other. The entrance can be on the end or side; cold way or warm way doesn't seem to matter. It is more an issue of convenience for you and the available flight path. If you are going to divide it then holes like the picture in the original post work well.
To make things easier, make your follower boards first. Use them for alignment when you mount the long side boards. Then you know they will fit without tweaking them. This really applies to KTBH builds. :)