There's already a thread on Cititel:
https://samleong.shop/showthread...103&highlight=
If you're staying at Cititel itself, you can call the spa and have them send the girl up to your room. I prefer going down to the Spa itself so I can use the facilities, and select the girl.
Last time I went was 3 years ago and the choices were all PRC. From the recent FRs, it looks like now got CKT and Viet. Do share your experiences after your trip!