Re: Splitting advice: nucs vs mediums
I think you are correct. I have and use a bunch of nucs - including some that hold 3 half size medium frames - but I have also used full size singles (8 frame mediums) as mating nucs with only a couple of frames of resources, closed bottoms and reduced entrances - and I can't see any important differences in performance - during the main season, winter might be different.
I used to use a special made wooden divider board to make it more cozy, but then I realized that a frame of undrawn plastic foundation works just as well. So just put the bees on one end and fill it up with plastic foundation - that way it's no emergency if they decide to grow.
I do agree that in a lot of ways they do better in tight quarters, but larger hives are easier to manage and require less attention. That's why there are so many flavors.
Don't let what might be best prevent you from doing what will work.