The usual way that a double works (at least IME) is that a provider I've seen a few times sets up a double by bringing in a friend of hers. And that's always been wonderful.

Decide on one girl you really want to fuck, making sure she has a doubles partner -- not so you can hire her, too, but that way you know girl #1 is more likely "really bi."  Also check her reviews.  Tell her you want to do doubles but with a girl she hasn't met yet.  Ask her for a suggestion and/or send her links for a few of your favorite candidates.  After she's picked one or two, approach the second girl.
My guess is it will maximize your chances of having a good time.
Best of luck

So the question I would ask you, is this something you would like to do regularly? If not, I'd tell you to stick to how you are doing it.

Yes, a lady likse to know whose pussies she may be licking.

Can I be honest for a moment? Ok. I ldo like to have my own doubles partners because I know she is into as much as I am, but I do offer to pair me up with another lady that the guy chooses. I have no issue with that. I would hope that she is a professional and has a clean and healthy kitty as do I. That is really all I ask. If she isn't really bi well then I can work around that, but for his sake, a really bi girl or a gay for pay girl will be the best for overall interaction. I luv to make a woman "O" and hey I know she's not faking! LOL!

People gamble their money in all sorts of ways I guess...  When you weigh all the time, money, energy, disappointments along the way, will the pay off if/when you get the experience you hope for be worth it?  If you think so, then good luck to you!

I figured 3 hours, but I never considered the getting acquainted time or the thing of one of them arriving late. And, as Nick pointed out, they each should have a history of doubles, not just "really bi" checked yes on their profile.

and do the impromptu dinner afterwards if so inclined.  

Thank you. One variation I considered is booking a long session with one and letting her know that a second lady would join us for 1 1/2 to 2 hours in the middle of the session. Hard to explain how, exactly, but I'm thinking that this would soften some of the issues involved with pairing.

And since each of the ladies are also flipping the proverbial coin hoping for heads to come up six times in a row, the odds sound more and more problematic.

I've done upwards of 30 doubles over the years and I have always found it crucial that the ladies meet--even if only by telephone--before we're all in the room.  No matter how nice and friendly the ladies there is bound to be some awkwardness, if not serious discomfort,  if they're expected to be naked and eating each other 5 minutes after they've shaken hands.  At  very least meeting for a few minutes beforehand will give them a chance to understand each other's boundaries,  preferences and willingness.  If you're determined that all 3 of you be strangers until you meet in the room then it's really a crap shoot.

Both times the ladies advertised as a double. One session was gfe, the other fbsm. One session the ladies were escort friends, the other sisters. Both times one lady sat around and did nothing, while the other tried to encourage her partner to participate, to no avail.  

She may well not appreciate that at all.  And how would you have any idea whether the two of them would have any chemistry?

reviews of their doubles sessions?  PM those reviewers?  Got to swing at good pitches if you want a base hit; otherwise you could strike out.

....unless I was reading about it in a Penthouse forum

But the 4 hands fbsm trip was the least thrilling. There seems to be a glitch in the doubles experience. The imbalance of an odd number is something all three have to work around, and it really only gets magical when everyone has wide boundaries and all are both excited and comfortable with where the lines are set. Sort of like never stepping out of bounds because the court is a few feet wider than regulation.

And my thinking was that chemistry would be less of an issue if an hour in the second guest arrives and simply joins an session in progress.

The comfort level seems more strained for the notion of two women meeting as strangers for a double than for the guy meeting the two women.

I think you're right. The two women should connect beforehand, and it probably would even be better if one of them could vouch for me, simply because otherwise it could sound too strange.

I'm often in search of this specialty and i can't tell you how many ladies have this in their profile despite the fact that not a single review mentions a duo.  It's easy for a lady to say "sure i do duos" when a client asks mid-session but if that client did not see the lady eating pussy then the correct answer to the profile question is "don't know".

I have joined with a gent and another lady before more than a few times and had alot of fun.
The times I have done this is with ladies who I already have done doubles with in the past.
I also have had a gent who I see when he comes to town decide he wanted to do a duo and he suggested a few ladies to me.I picked a lady whom I had never met before and he made the arrangements me and her spoke as well.Before meeting for the appt her and I met up to talk and to see if we would get along well together.We all had a great time.

I love doubles, but with very few exceptions I've had the lady I already had a "relationship" with invite one of her friends to join us.

A couple of times, I've put two girls whom I know together who had not met, because I knew each of them well enough to know that they would hit it off.

Two strangers?  Nah.  You're trying to hit a grand slam here, but more likely you'll get a single or double (or even whiff).

Which did happen spontaneously, so yes a threesome can happen spontaneously and still work.

I did a foursome with three chicas in Costa Rica a few years ago with a chica I was dating, a lesbian friend of ours who had always wanted to fuck my GF, and a hooker that we picked up for the occasion, mainly as someone for me to fuck while our lesbian friend was getting in on with my GF.

Long story short, it worked like a charm and was one of the more memorable evenings of sex I have had in my life, even though the only two of us that had ever been together before were me and the chica I was dating. The chemistry was still there and a great time was had by all.

It might be hard to duplicate this in the states as most P4P encounters have to be planned in advance, before the parties have had a chance to meet and see if their is any chemistry between them. In my foursome encounter well all got liquored up at the bar first, and it just sort of happened, something very unlikely to happen in a country where prostitution is illegal.

I have a suggestion since you have obviously got a pretty decent budget set aside for this. Why don't you go to a country where prostitution is legal, find a bar where there is "action" and find a couple of women that are up for this. Panama, Costa Rica and Colombia are all a short plane ride from the States, you could easily hop on a plane, enjoy yourself for a couple of days, and still spend less than five grand going first class all the way. Not to mention you wouldn't be limited by budget to only a two hour session. You could do an all nighter with two hotties two nights in a row, pay for your plane ticket, a decent hotel, eats, drinks and still keep it under five grand for the weekend.

but for my first (and second) I went the route of seeing two providers who I'd seen individually but that just started advertising doubles together. As it turned out, I was not only their first as a duo but it was one girl's first bisexual experience. It worked out so well that I did it again a couple of weeks later. I'm not saying this is a recipe for success or anything but it worked out well for me. And to be honest his post is more like what the guy said when the Protestant minister asked him why he confessed to him about having sex with his girlfriend and her mom: "are you kidding? I'm telling everybody!"

I like to meet up with the lady for coffee first, then proceed. I have been asked before with a specific (hot) provider in the request, and I've said no. I just have to feel comfortable and not vulnerable.