How do you accommodate the growth of the colony when the equipment is non standard?
These frames and boxes are not for raising nucleus colonies, but only for mating queens with. I agree wholeheartedly with your point that if raising a nucleus colony which naturally expands - then sure - keep them on standard-sized frames from day one. Any other approach is nuts (imo).
With these mating nucs, the principle is similar to the use of mini-nucs - i.e. they're setup with the smallest viable colony; queen-cell emerges, queen is mated, lays a frame or two of eggs, then removed. Next queen-cell is added, and so on. If the small colony should enlarge a little during this process, then the number of frames can be increased from 3 to 5. Some people pull the divider - Mike Palmer being a good example - to enlarge the colony to a box-full of frames, and even stacking those boxes and over-wintering them, thusly:
... but I don't intend doing this. The key to the setup I'm planning is in maintaining a common footprint, or a simple divisor of it:
The British National Hives I mainly work with are square, as in 'A' above. The 5-frame Nucleus Boxes are Half-Width, as in 'B', with two fitting
exactly over a standard Brood Box. Discrete standalone Mating-Nucs could then be quarter-sized - but I've decided to maintain a 'B' footprint, divide this in half, as in 'C', and run the smaller frames
across custom-built boxes, rather than along their length. Thus far, my system is more-or-less identical to Mike Palmer's.
By retaining the divider and common footprint division it creates, combs for the smaller mating frames can be initially drawn-out over a colony housed in a standard half-width nucleus box, and colonies then formed by installing nurse bees through a queen excluder. Then, when the season is over, and these small colonies made queenless again for one last time - the remaining bees can be easily combined with any queenright nucleus colony housed in a standard half-width nucleus box. Thus, these custom-sized frames (and dividers) never get to leave their custom-built boxes. Or at least, that's the plan ! (Famous last words ...)
Van - wishing you great success with your AI/II - I once looked at the cost involved for equipment and the amount of time it typically takes to become proficient ... it's definitely not a technique for the faint-hearted !
LJ