thoughts?

Look at the top 100 provider list for Vegas.  Find providers that seem as if they'll float your boat (based on their photos, which "advanced degree" they claim they have, your own budget, etc).  Check the reviews and their websites.  There are some who don't do duos, but most of them do, and usually list their preferred friends (always better to find providers who have pre-existing rapport).  See if you can find reviews of the girls of your dream as a duo--you may have to do some digging through the reviews of each provider separately to find that one review of the two together.

I think it's safe to say that if you already have an ATF or two in town, the easiest thing to do is to ask her if she has any friends that she likes working with.

I got kind of weirdly lucky when I started looking for duos:  At that moment, let's just say that I was looking for a particular type of experience, and was looking for a certain "type".  I scheduled two different appointments with two different ladies, within a few days of each other.  By the time I met the second one, she had already heard about me from the first (they weren't just work-buddies, they were IRL besties)--and proceeded to tease me about how I "could have had both together".  That was a mistake I soon rectified.  I saw them together for years after that, until one of them quit the biz earlier this year…  But great times for as long as the ride lasted.

This is why I recommend not just trying to "mix and match".  Find a provider you like, let her know your interests, and let her use her judgment about who your third playmate should be.  You'll rarely be disappointed with this approach, IME.

Great advice.

Had a long time fantasy of finding two ladies who really want to play with and explore each other, but have never gotten the opportunity.  Would like to sit back and watch them get acquainted.  Something about watching that first time passion is very exciting.

I have a list my list !

f I were a hobbyist in this Town, I would go broke,  but have a hella good time doing it !

First, if you know neither of whom you'd like a 3some with, BE SURE they know each other.
From 1st-hand experience, I'd recommend Nikki Avalon and anyone she'll choose, though I'm partial to Nikki and Victoria Westwood together.  Or, Nikki and her new friend from Az, but that's a whole other story, and not for review nor publication.  
Suffice it to say that Nikki is such a great giver that I don't know anyone she doesn't get along and play well with, so consider her for your top choice, and ENJOY!

We make a great duo!!!

LOL!  ^ 5's!   except for the mention of the "new friend", tsk tsk.  And yea, it's paramount that you coordinate with the Nickster!   Trust me on THAT!!  

Thanks for the mention  You're on my list, along with Heather Jana!