Sorry if this is in the wrong forum, it deals with creating queens but also a management technique.
I've been reviewing the two queen systems and comments about the extra work involved in managing them. I'm trying to wrap my thoughts around the ideas and combine several of the techniques to do multiple objectives.
1. Create an early split above a queen excluder using something similar to a split board or snelgrove board. - Our drones start flying here probably early April, weather can still be cold and by utilizing a excluder I could make use of the heat of the lower colony that is to be split. In making my split board I would use excluder material so nurse and workers would be able to transverse between upper and lower boxes. Using an upper entrance similar to the snelgrove board could in theory allow the queen in the upper box to mate and return to the upper entrance making a two queen hive. If she were mated and started laying mid April would help increase population in the hive for a May flow on clover. Instead of letting the workers make queens, I could introduce a ripe queen cell to hatch and save about a week or so.
2. After several weeks of buildup and prior to large May flow I would remove the queen and a some brood plus nectar, pull them out and place into a nuc box for additional buildup.
I'm not sure if this would work or if it would just be easier to make 3-4 frame nucs from the beginning?
I was hoping the two queens would be able to buildup enough force to make a honey crop and also create a nuc division or split.
I guess it depends if you want more colonies. If I were going to elevate brood and ask them to raise a new queen, I wouldn't use an excluder...at least not at first. You mention Snelgrove entrances. I would elevate the brood and bees above a Snelgove board with a rear entrance open, or the inner cover with rim up, escape hole closed, and the entrance in the rear. Once your queen is laying, I would move the nuc to a new apiary, or move it off the hive and behind the hive facing back. It will be a new colony and won't lose bees. Or you can replace the screen or inner cover with an excluder...better done once the new queen is laying, and run the hive and nuc as a 2 queen colony...until you use the nuc to requeen the parent.