https://toplessvegasonline.com/
Note that the site has a preference for the clubs that advertise there but it's still great info.
Best looking girls: I'm picking Spearmint Rhino but others may says Sapphires. Both clubs have lots of dancers (easily 100+, I think Sapphires claims 400+ at times). CH3 and Hustler Club are good sized clubs that may be worth a visit. Palomino is a fair distance away from the strip but they're the only club that has a full bar and nude dancing, and they have some lookers. For no booze nude clubs, Little Darlings is hard to beat.
Extras in a Vegas strip club? Unless you're willing to drop a shit ton of cash, I wouldn't bother. Most dancers do not have to do extras to make a ton of money in Vegas. How is your meager offer of tips compare to what she makes during a large convention week? Why would she want to get kicked out of the club for getting caught doing extras? Vegas is fucking expensive and if you aren't willing to part with a large amount of cash to have the fun you seek, save it and keep it in your pocket.
Cheetah's has $10 lap dances and drink specials 7am-7pm. Talk of the Town is an interesting spot. There's early evening happy hours at some places (I recall Hustler Club and Treasures). Deja Vu Showgirls has some drink specials ($2 Tuesday is probably the best drink special in any Vegas strip club where beers start at $6 if not more at most places and I remember paying $17 for a well vodka tonic at Sapphires some years back). Not sure if the lunch specials are just during the week or on specific days but you should look into that (my fav Spearmint Rhino has a decent one).
stripclub recommendations?
