In response to your swarm-control description,
 
It sounds like a good plan.  One thing to add is -- by the time they are
getting ready to swarm (you find queen cells under development) you would
normally have at least a couple of honey supers on already. These will have
had some progress made in them already, from the early nectar sources.
 
You want to put the queen and a comb of brood in the center of your new
hive, on the orig. stand, then the excluder, and then whatever honey supers
there were, with whatever bees are in them.
 
Then you can put the screen/divider on, and the original brood chamber(s)
above that.  You can set the divider so that the upper colony's entrance
faces front or to one side, and then later when you re-unite them, the
field bees will find their way in OK.
 
This is pretty much the "classic" artificial swarming maneuver, except you
are putting the main hive on top instead of to-one-side.
 
The upper colony is not likely to swarm at all, since they lose all their
field force to the hive below.
 
It would probably be easiest to put the comb where you find the queen at
the center of the new hive, and then add a comb of sealed brood on either
side.  This will prevent you from having to pick up the queen (squish!),
and it will provide some soon-emerging bees to the lower unit without
inviting swarming.
 
In about a month the upper colony should be getting strong and the new
queen should be laying well.  Then you can unite them as you like.
 
A potential hitch here is that the foundation in the bottom (new)
brood-chamber might not get drawn very well, being so low in the hive.  You
could always go in there after they are all united, and move it up to the
3rd position for finishing.
 
You can let them fill that third brood-box with honey and harvest it,
leaving a 2-brood chamber colony for winter.  Or, winter them in all three
(not a bad idea in NH) and next spring remove the bottom one - by then
empty - when you clean off the floor.   Next time you do your artificial
swarming, you will have a brood chamber of empty drawn combs all ready to
go...
 
(BTW I had bees in Alton, Meredith, and Dublin for a few years)
 
Good luck, Alden.
 
JG