A properly managed 2 queen colony will produce more than two single colonies, or that has been my experience. For instance all my 2 queen colonies averaged over 300# of honey each, while none of my single colonies averaged over 125#, side by side with each other. When I experimented all mine were verticle 2 queens, and to much extra work. Lifting 60# medium honey supers over your head gets old in a hurry. Michael Bush's site has suggestions for horizontal 2 queen colonies which would take care of this problem, but I have never tried the horizontal colonies.What is the advantage, if there is any, to double queening a hive? Seems like less trouble to just make 2 hives.