My contract is for multiple smaller blueberry fields, so I went with the 4 hives per pallet so I could split them up to different fields a bit easier.
I had considered that all boxes would have to be "on" for the cover to fit the 4 hives. Not a problem if they are all strong, but as you said, it will be a problem while they build up, especially if they build up unevenly.
I have room to the front of the pallet and behind it, obviously cant have anything sticking out to the sides, so it means I can use a bar across the front of each hive, but cant have any other protrusions.. worried the plywood will warp, though I am using reversible inner covers, I'd still like to keep the weather/rain out as much as possible. So basically, if one box is behind.. IE has two mediums on it and the rest are running three the reversible cover will still keep the bees enclosed while the large cover will hopefully keep the rain out?
Heading up to tinker for a couple hours, will get a picture of what I mean.