David go it right when it said it is hard to introduce virgin queens.  I would
endorse getting the umbrella out as I have had a lot of experience under an
umbrella in the rain.  Queen rearing has to be carried out on the day.  No
time to procrastinate.
 
On the introduction side, I have introduced emerging queens into a nuc from
which the queen bee has just been caught many times with success.  Maybe it is
the disruption of catching the queen that increases the acceptance.
 
Brian Sherriff from England told me several years ago that he used to buy
virgin queens and introduce them to queenless nucs.  As I recall it he had a
queenless nuc (not sure how long it had been queenless) and went to the nuc
just after dark and ran the virgin in with the aid of a little smoke.  Brian
said he had good success rates.
 
Also I have found that if the virgin queen is older i.e say 6 days as against
1 or 2 days, the acceptance rate is better.
 
Hope the above helps.
 
 
Trevor Weatherhead
AUSTRALIA