What I have noticed is that if you wait 5 days and emercengy cells are capped, the hive accept easily new queen. Same is in the reseach.
Keep 2 days without queen. Difference is that bees have started to rear new queens. They may accept a new queen or not. During main flow you just put the new queen onto combs and it is accepted. In August when there is no flow, its 90% sure that bees kill the new queen. During winter feeding it is easier again to change the queen.
I do not trust smoke. I have used it 40 years ago when my menthor told about the method.