If you'll forgive me saying this, I think you are making incredibly hard work of it. All you need is a floor and a spare brood box filled with comb and a few foundation.
If you find a colony with started queen cells and they rebuild them each time you knock them down, the colony is clearly determined to swarm.
The way that I deal with it is to remove all boxes from the parent colonies stand and replace them with the box of comb and foundation. Remove a comb from the centre and replace it with a comb of open larvae which you take from the parent colony (make sure the queen is NOT on this comb and that there are no swarm cells. To do this you will need to shake the bees off the comb and thoroughly inspect the comb).
All the foraging bees return to this box and will cluster on the comb of eggs/larvae which is all they have. You add a super of open honey or a deep frame of pollen and open honey. This gives them food incase the weather turns nasty. Place a cover ontop and leave it alone for 9 days.
The parent stock contains the queen, all of the brood (except the frame you took to put in the bottom box) and the nurse bees. Go through this hive thoroughly and remove any swarm cells. Now place it on the top (or behind if the stack is too tall) but pointing in the opposite direction. Any flying bees will return to the original site with its entrance to the front. Close the queenright stock up and leave them alone.
After 9 days, the queenless stock containing all the flying bees and the single frame of brood will have built emergency queen cells (it has no queen). You take this frame out and shake off any adhering bees, then you destroy all emergency cells. This frame is replaced with another frame of young larvae which you take from the queenright parent colony exactly as you did before.
The queenright parent colony will have lost all of its flying bees to the queenless nuc so it is unlikely that they will have any swarm cells but you can check to make sure. The population will have been drammatically reduced. After this you close the colonies up and leave them alone for another 9 days.
At this point you remove the single comb containing emergency cells and destroy them. The swarming impulse will have gone by this point so you can recombine the queenless box (containing only nectar/pollen that the flying bees have collected) with the queenright portion (containing the queen, brood and all the young bees) using a sheet of newspaper between the boxes. They will reunite and continue as a productive colony.
