I like the Wynn, it'll be a good choice. Caesar has a nice pool as well for topless bathing. Both seem to attract a mature crowd.
If you need help with the tanning lotion, I'm willing to help...jus sayin.
Enjoy your trip

Several Choices...

Bare Pool @ Mirage | Daydream @ The M | Marquee Dayclub @ Cosmo | Moorea Beach Club @ Mandalay Bay

Tao Beach @ Venetian

Pools are really relaxing at this time of the year. I believe cold bath from pool really relaxes the body.

You are right Wynn is the good choice it has perfect direction and not really expensive according to the service they provide.

If you even want to try out the pool party their's a club naming sapphire they arrange some cool pool party but I doubt their pool starts from June.

Anyways - Make Sure You Enjoy Your Trip