Mine are pretty much in sync with the wild ones from the same locale. They are eclosing in their pupal cells from September to October. I wait until each fresh adult is well hardened off, about three weeks before putting them into the cold. I hibernate them in my attic, so when they first go in there the temp is usually around 55F. It gradually cools down in there as the outside temps drop. The lowest it ever gets there is about 36F.
You definitely do not want to wait for them to emerge from their pupal cells and then put them in the cold!