Always pay up front for BP MM. The first time, always ask MM to remove her dress first or want her to touch your dick before hand her the money. The cop won't do those things!
Hey bro I am kind of new too. Not a lot of experiences but I think most (like 70% or more) will ask you to pay first.
I think agency is definitely safer. My buddy is very experienced hunter and he told me many bad experiences with backpage and independents. But make sure you go for those agencies that have good reputation and been around for many years. Roommates is very good i heard. Don't go for those new agencies with really glamorous websites and too good to be true pics.
Stages for me.
First FS with indie,. Then shops.
Reason,. Indie one on one is legal on mm part,. Not me though.
Shops may be considered as more than that. ie more than one , though still one in unit.