I have been following but no comment till now:
I have been waiting for someone to comment on the 4x4 njuc set-up Palmer uses. Palmer attributes the system as the core foundation of success of his whole operation. He was shown the system by Kirk Webster and Palmer has not looked back since seeing the system. He runs a yard of 600 4x4 nucs alone. No it is not keeping in just 5 frame nucs but it shows how valuable the system can be. I will not go into details of the system as it is easy to find multiple presentation by Palmer on the 4x4 system.
My experience with 5 frame boxes here on the warm East Coast. They absolute build up quicker if you start with 5 frames and then add the next five. They build comb much quicker as they are confined to a smaller space. And yes watch them close or they will find the trees quicker also. My limit is three boxes of fives but I hear folks mention five? At three or above I find they are quick to want to enter swarm mode. As far as winter I can winter two five deeps stacked with no issue at all. I plan to crowd some next year during flow to try some comb. The bees in the tight space usually stay away from having drones.
At three high I have had no tip overs but I will go today and all will be on the ground
To avoid that Palmer puts his on a standard ten frame bottom divided into two four frames. He then stacks a fours on top of that (each side) and sometimes a third four. Having them together on the wide base gives stability but most importantly warmth in the winter. Larger hives of course make more honey. Palmer uses them to recover his bee losses and also uses them to supplement before the flow as BEE BOMBS.
This has been a little off the track of keeping in just 5 frames but I think it shows it absolutely can be done. Keep them two strong and the third box is usually nice deep frames of honey. Extract that top box and add another and repeat. They may not make as much but the handling will surely be easier on someone with back issues and as said above everything will fit.