In our case, we are running only 8 frames and an inside feeder. A double is probably holding half again as much brood and lots more pollen stores. For best results running 10 frames and bottle feeding them would no doubt result in better bees but that's quite labor intensive and presents some logistic complications. Despite all that if you get a good late summer flow the populations in a single aren't too far behind the doubles and if they can average 7 combs can get you an almond check for about 1/2 the shipping costs.Jim, I have thought about the shipping charges. I have had terribly large singles going into winter before. Why do doubles generally look better in the fall?