I'm not sure how to address this scenario. Let me try -
Context/Given - A provider you are interested in, posted their planned tour schedule but isn't coming to your city. You know they have been to your city before and visits often, but you don't know when they will be back.
Should you send email and inquire about it? Should you provide screening info before they ever plan on visiting/at time of initial inquiry or Do you provide screening info when you know they are touring in your city?
Personally, if I knew she was a regular in my city and I wanted to strike while the iron is hot when she returns, I would reach out to her and introduce myself and tell her where I live and that I want to meet her on her next visit and then politely ask if you can screen now. I don't know any lady that would refuse. It can't hurt to make an inquiry.
There is an agency in DC that won't pre-screen you and will only do it when you're ready to book. It's difficult for me to operate that way.
You fill out a tiny form that asks your name, email addy, along with your city, and they can reach out prior to touring your town. Many women will not want screening info without a specific date request as that I just extra work, but some will.
.
Personally, I would not provide that info to a provider if no tour was planned. What I do is just keep tabs of their website, twitter, tryst, etc and keep any eye on their tour schedule.
Mainly because you don't know exactly what info she uses to screen. Just tell her of your interest, ask her when she's coming. If you want, also tell her you'll provide screening info upon request.
I've done this before. I reached out to a few ladies If i knew they would they traveled to my city alot. I would just give them my info and references and let them know I just wanted to get verified before hand and that when im ready i would give them my info again if they would like. If the are local I would just tell them i would like to see them in the future and hear is my info. They usually say thanks and let them know when I am ready.
Yep, I've pre-screened with some companions before. One I have yet to meet (I keep missing her when she's in my area) and another I have actually met. As for ladies I want to meet who don't plan on visiting anytime soon, I've made contact with a couple and do a combination of asking that they let me know when they'll be visiting my area and occasionally looking at their ad/website for travel/tour updates.
I think it's fine to get the screening part out of the way. Then, you can focus on booking the date when you'll both be in the same area. 
Bro, I can tell you are new at this. Why would you provide screening information before they every plan on visiting your city? Even when everything is planned and done correctly, there is a 90% chance the hook up will not happen because providers are extremely flakey. Try not to be so eager to see a provider. They come and they go. When you see well over a 100 girls, you will understand and be more patient and pickier.