We introduce many virgins each season. I have tried various methods throughout the years and find that treating the virgin is LESS important in a successful introduction then the condition of the receiving bees. As stated earlier in this thread, if the receiving bees are psychologically receptive to a virgin, the chances for success greater: what is psychologically receptive? Queenless, younger bees would be very receptive to a virgin; bees that are expecting a virgin.
I'll use a Benton (3-hole) cage or JZBZ cage with either a tiny bit of a candy plug OR one layer of paper rubber-banded over the entrance. Introduce the virgin in this to, small nuc populated by young and emerging bees.