Sorry I didn't reply earlier. Fortunately, you got some great info from the gang.
I'm no expert on paying for SA anonymously, as I'm not married, have no SO, and my closest friends know (or strongly suspect) that I live in the Sugar Bowl.
Your questions about how to manage the discussions are on point. That's really the heart of the success/failure dynamic. In general, as mentioned, keep your messages on the site far away from any hint of quid pro quo language. Even if/when a POT asks for an amount or mentions explicit sexual acts don't reply in kind - that's an instant ban from the site.
Instead, spend a minimum amount of time talking on the site and quicky, graciously move the chat off-site to text, what's app, google voice, snapchat, even email.
Try something like this:
"I'd really like to set up a brief meeting soon to see how well we get along and discuss the details of an ideal arrangement for both of us. Here's my text number 999-999-9999. You can message me anytime that's convenient for you."
Now you still need to be careful with messaging even when you move off-site at first. Go through at least 2-4 message cycles before you get too detailed. Or let her take the lead and ask more specific q's. Note you don't have to give her a $$ number yet, even if asked. But you can get into a deeper discussion about date frequency, activities, likes/dislikes, and expectations. I recommend you stay away from offering or agreeing to any amount until you are face-to-face. You will have a much better chance of negotiating an allowance you are both comfortable with once you have established some personal rapport together. Of course if she insists, proceed with caution and be willing to walk away if she's asking for too much.
Remember this is dating site. Yes, there is a certain monetary structure to these dates, but still, wait until you are comfortable that you are both on the same playing field. If you feel like saying something that you would not say to a woman you just met in a supermarket, friend's party or at a concert, then say something else. She knows why you're both talking, so work the other aspects of your potential relationship 1st.
With the last POT I converted to BCD about 2 weeks ago, I only mentioned an allowance as she got out of my car when I dropped her off after our M&G. "I'm really looking forward to seeing you next Saturday. And I'm happy to help you out with your bills as well. Will $300 work for you?"
It did, and six days later I dropped a load of... $20 bills on her... right after I dropped a different load in her sweet mouth.
Life is good
The Cat