I used to introduce my queens with their attendant bees and got a pretty high mortality figure. Last month i tried the other way and that was removing all the attendant bees and introducing the queen alone and my mortality rate went way down. the reasoning i"m using is that sometimes the attendant bees are older bees by the time you get to introduce the queen, and the queenless bees view them as intruders and become vicous towards them including the queen. To remove the attendant bees, get hold of flat sweezers and remove the cork on the cage. Push in the tweezers and grab the attendants. This is done preferably in a room with windows closed in case the queen manages an escape.
Before introducing the queen, we examine the hive to make sure there are no queen cells. Once thats clear, i put the queen with the cages corked between two frames. After 2-3 days I examine the queens and the bees clinging onto the cage. Any sign of aggression and i remove the queen...for sure she'll not be accepted! More often than not, the bees will be calm and you can see the queen begging for food and the bees feeding her thru the cage. Once the bees start to feed the queen, thats almost 100 % acceptance and we go ahead and remove the cork and let them eat her way out thru the candy.
The safest method for me, but the most in work is this method. We remove a food frame and frames of emerging brood....no larva or eggs preferably. We make the nuc sit beside the mother colony for a day to encourage the adult bees to go back to the mother colony, leaving the nuc with mostly baby bees. Then we move the nuc to another location far from the mother colony. In 2 days time a lot of the bees would have emerged and not having any larva, have nothing to make a queen cell from. This however is not fool proof, so we still examine the combs for any queen cell. If there is no queen cell, we go ahead and uncork the queen we are to introduce. Acceptance is very good since the nuc contains mostly baby bees. If they have managed to make a queen cell, we destroy the queen cell and introduce the queen several hours later this gives the bees time to realize they are "queenless" once again.