B2BFK

R$400 at Lagoa in June. But OMG Felipe was (is) stunningly handsome with a completely disarming smile, possessing a girthy 25cm and performed with incredible passion. We were both really in to it and he was clearly exhausted when he just collapsed on me after.

No. It would be prof escorts, porn stars, guys escorting in Europe or the US, etc. Guys that have build up a reputation and are in high demand. Just because a guy has a big cock, muscle or is handsome/a model doesn’t mean that he should ask for prepayment and you shouldn't agree to it. 

Prepayment for escort services/to guys off Mileroticos? Full stop! It doesn't work this way in Colombia and any guy asking you for prepayment is likely to scam you, i.e. you will never meet him. 
If a guy ask you for prepayment, just move on. Not worth it/the risk.
High profilers as mentioned in this thread may be exceptions, but for normal Mileroticos guys in Colombia; no way!
However, you don't schedule Mileroticos guys several weeks in advance. You contact them when you want their services; same day or the day [edited to "before"]. If you message them far ahead you will not be taken seriously and viewed as time waster (with most likely no real intention to meet); trust me these guys get lots of messages from clients with no intention to meet and they are fed up with it. 

Just adding everything @speedoo1 explained here is 100% correct. 
 

I'm finding it fairly tricky with some high profile providers. Caio was the exception - extremely organized, extremely professional. For many with substantial OF followings, however, I suspect escorting is an insignificant part of their revenue stream (I'm sure that's true for Caio) and for some that means that they don't take it seriously. I lucked out on catching Roxas Caelum on a 24hr visit to Toronto (client paid?). Nice guy, nice experience. I had no problems arranging an appointment with Ray Diesel when he visited London (nice but talks too much). I had a fairly long, pleasant WhatsApp chat with Luccas Toblerone which unfortunately ended with an appointment that he flaked on. Same with Kau Cobra. I tried to arrange an appointment for a month ahead with FullMetalTwunk when he was visiting Paris - all I got was a "Sure" and his rate, he ghosted me after that as I tried to set up a date and time. Oh well. It's hit and miss.

I contacted him through RM. He has an apartment in South Kensington, London. I made an appointment  at least a month in advance with a deposit. Very professional, very polite (stunningly beautiful in person). His current rate is £500. He is currently in Milan.
https://rent.men/CaioVeyronXXX

I contacted him through RM. He has an apartment in South Kensington, London. I made an appointment  at least a month in advance with a deposit. Very professional, very polite (stunningly beautiful in person). His current rate is £500. He is currently in Milan.
https://rent.men/CaioVeyronXXX

We had a discussion about time (not a good idea to be still negotiating terms while having sex but ..) so a new rate was negotiated. I didn't have the cash but he agreed to accept Pix. I have an app(PaySend) which allows someone outside Brazil to use Pix (it's for bank to bank transfers within Brazil). It's supposed to transfer within seconds. After an hour it had not completed. I took back to my hotel and payed him the cash. An hour later Paysend tells me the transaction has completed. Rodrigo denies receiving the money. Paysend says that it transferred it to his bank. Unfortunately, unlike PayPal or Interac, there is no auditable way to verify the recipients acceptance of the funds. So he got paid twice. The sex was good just not that good.

The one I'm really sorry to have missed is Puepos Ramos. We just kept missing each other in messaging and I think he thought I was just a time waster. Maybe next time

I only checked one of the garotocomlocal links you shared, I hope it is representative. Joseph Santos' profile was created in 2019, and its last update is from longer than a year ago. They may be no longer escorting or they may be not paying attention to the contact number/email you used. If you know their Instagrams, you may want to try again if you want to get their attention, but be ready to receive a negative response. 

Coimbra has publicly said that he doesn't escort (https://youtu.be/DZ5b1CDTuLo). 
Luccas Toblerone is on RM in SP - currently in Paris (https://rent.men/Luccas_paulo) - He made an appointment with me then flaked.
Kau Cobra is on RM in SP (https://rent.men/kaucobraXL) - He made an appointment with me then flaked.
Leonardo Leeme is in SP https://garotocomlocal.com.br/acompanhante-masculino/leandro-leeme/ - I sent him my RM profile and he ghosted me.
Joseph Santos is in SP https://garotocomlocal.com.br/acompanhante-masculino/joseph-santos/ - no response
Rick Dotadao is Belo Horizonte https://garotocomlocal.com.br/acompanhante-masculino/rick-28cm/ - no response
Marcos Quinho is in SP https://garotocomlocal.com.br/acompanhante-masculino/marcos-quinho/ - no response
I think a lot of these guys have sufficient OF (or Privacy? - can they make enough on Privacy?) income that escorting is just a side-hustle that they play with but aren't serious about.

As a newbie, definitely stay away from online in Brazil.
Stick to the safe saunas.
Assuming you are reasonably fit and have no mobility issues, here is a draft plan just to throw out some suggestions:

A nice easy first trip might be one-two weeks in Sao Paulo.
Get a nice hotel on Paulista Avenida.
See great museums during the day.
Around 3:30-4:30, take an Uber to Espaco Lagoa Sauna.
Bring ear plugs, seriously.

Like you, I like affection along with serious sex.
You can definitely find handsome young men who will be highly affectionate (I have found some great guys on this current trip), but they will vary a lot. In my experience, the most highly affectionate GPs tend to be bottoms, but some tops can be great at hugging and kissing.

Finding them can be tricky because most will claim they like to hug and be romantic, but that does not guarantee they will follow through in the room.

Be cautious about making much eye contact unless you think you have at least a semi-finalist to "interview."  More and more of them have Google Translate on their phones now, so communication is not too difficult.

It sounds like you might be at risk of having your heart broken and be seen as a sugar daddy monthly ATM if you are not careful. So try to resist falling in love right away and being exploited. Many posts on here discuss payment strategies.

Let us know how it goes.