I find this idea quite interesting.
My vote goes for ... I Am CandyGirl #7. Sidonia is a top CandyGirl.
I like SP Club, as mostly I have good experiences there and the atmosphere is friendly and relaxed. The girls are nice and friendly 
Just one suggestion: it would be good to have some games there, it helps to kill time when waiting for a girl or waiting for customers. It would also help to make contact with the girls.