OK - I'll go out on a limb and address the "how much" question. In full disclosure, I haven't done the Rasul, but if I did, I don't think I'd tip as much as I do for massages, facials, etc., because let's face it - other than letting you in/out and explaining the products, the spa employee doesn't actually DO anything unlike those other more "full-service" treatments! To me it's the same as the distinction I make when I'm at a buffet restaurant vs full-service. I tip the person bringing me drinks, but I don't tip 15-20% of my full buffet charge! I usually tip 18-20% at spas, but for the Rasul-type service, I think I'd go with no more than 10%. But that's just my rationale......