I've been raising queen cells using the Miller Method to make queenright a couple of colonies. Typically I get about 7 - 10 queen cells. Then I destroy all undersized cells and keep the best looking 3 - 4 cells to emerge, hoping that this improves the odds. I've had about 50% success so far.
My question is - should I be keeping only a single cell to emerge, or is there a benefit (or problem) with keeping more than one?