Quote from Poppagator
Instead of a number of songs, performers should be allotted a number of MINUTES. Then it's up to the performer to decide whether to do a lot of short numbers or a few long ones.
End of quote

Thats what I do at my club. Wouldn't have it any other way. Its up to the performer to decide what they are going to do in that allotted time - talk, tell jokes, sing etc.