Depends if you like it super slow (but fewer hotties), or party atmosphere (more hotties -- but a sellers' market). I like it super slow. As a general rule, the best times are any day from 1pm-4pm (you miss the lunchtime rush and the happy hour rush) or Sunday-Thursday 7-10 (nightshift is usually slow until 10-11).
But individual clubs vary. One of the clubs here gets packed on Friday afternoons, I mean packed like a nightshift, so I don't go to that one on Friday afternoons. Another club gets loaded with girls on Saturday afternoons and Wednesday nights, so those are primetime. Why Saturday afternoons and Wednesday nights? Saturday afternoons because all new girls have to work 6 saturday dayshifts within their first 3 months, and also because Saturday afternoon is often the penalty shift for nightgirls who got in trouble with mgmt for some reason. And Wednesday nights, because this club has a rule that if you want to work the lucrative Friday night and Saturday night shift, you have to work two "slow shifts" during the week, and Wednesday night is considered the last slowshift of the week, so the strippers pile in.
Point is, there may be some pattern to each of your local clubs