Before I retired, I was on travel across the US about 6 times a year, and internationally about once a year. Here's what I recommend in general when planning to travel, based on my own experiences with typically a 2-4 day trip:
1. Timing: The optimal time to start contact is 3-5 days before you arrive, assuming you can meet within 1-2 days of your arrival. Start later and the logistics of vetting and scheduling take more time than you have. Start too soon, and risk losing her interest in a one-date hook up.
2. Your travel pitch: There are generally SB's that will be happy for a one-time date. But they tend to be semi-pros, or fulltime pros and you can expect the date to be much more hooker-ish: Higher rates, more "safety" requirements, less time, no effort for emotional connections. But if you present yourself as frequent traveler to her city, like 2 times a month, you can tell her you are looking for an ongoing arrangement. This can be the ideal arrangement for an SB who dates multiple SD's. You will show up, drop some sugar (and a few other substances), then leave her free to date the next guy. Then two or three, or a month later; wash-rinse-repeat. So decide on your pitch before you message.
3. Date Budget: Be prepared to spend 10-50% over your local budget. You may need to sweeten your offer of cash, dinner, etc. to assure you can compete with the local SD's in the area.
As for Mexico City specifically, I have experience as a tourist is other cities in Mexico (especially TJ and Cozumel), but not the capitol city. A few things to contemplate that apply to any city there:
1. You may not need to use SA, although there are plenty of profiles from Mexico. Prostitution is de facto legal there, meaning you won't risk being arrested from a LEGIT LE officer. If you use SA, be prepared to pay rates higher than hooker rates, but as you might expect, you should get a more dating-ish experience.
2. Many of the hookers that work in the local bars have social media, a following of "clients" or SD's, and will gladly agree to meet outside the club for a sugar-like experience. You will likely need to meet her 1st in the club, then try to bond and earn some trust before proposing a "date".
3. Speaking Spanish, even at a rudimentary level is VERY useful. Hookers will know enough English to book a session. But maybe 25% of them will be more fluent in English. A "regular" (SB) type of girl may be better educated. And she may have better English skills, especially if her education or job requires it. If you speak decent Spanish, you will build more comfort, trust and respect with her quickly. And you may avoid an uncomfortable experience when a misunderstanding occurs due to a language problem.
4. Know the currency rates. In TJ, hookers will gladly accept USD. Not sure if that applies to Mexico. It is a fairly large and established city, with well-developed culture and more modern (than TJ) infrastructure, business districts, etc.
5. Back to LE. Be careful to NEVER piss off a cop in Mexico - any cop. They are under-paid and easily corrupted and can even be part of a shake-down scam set up by a SB (or her pimp, or crime lord). Keep your head down, don't be a typical entitled American Tourist Jerk, and do not carry large amounts of cash or lots of credit cards outside. Leave it in your bank, or at least in your room safe (note: don't assume a room safe offers total safety). If you are shaken down by someone, offer up that $100-$200 in cash you have in your wallet as "all I have, Senor!" and don't mention the $400-$1000+ plus you left in your room.
Finally, I know there are others here with specific info on Mexico city, or who may have a different take on my advice. So please look for those replies before you book anything specific.
Life is good
The Cat