If you're referring to the performance score then I would skip that tag team. But if it's appearance I would say think about the double.  Not everyone's 7 in appearance is your 7, but when it comes to performance 6 and 7 are basically our way of saying they were pretty good but nothing to write home about. Of course I'm talking about ladies with consistent 6s and 7s, not just a few scattered among 8 pages of 9s.  Anyway the double is something you can't do all the time. Furthermore its something you can't get from girls who are truly into it that often.  Sure quite a few might be "bi for business" but only a very few really go out of their way to advertise and perform with their friends very often. One girl in your area is Sexy-Curves, she does it and she is VERY good, She is usually partying with a very adventurous girl and they will teach you things, man will they teach you.  If you see a girl advertising a duo with her friend, talk to her, find out how well her and her friend connect, if they do duos very often, what fun they plan for you etc.  Also internalize for a moment, are you there to watch or participate equally or do you just want an extra tongue around to pleasure a girl you really like.  Tell them which version interests you, if it's the latter you can get that a lot easier than the the first two.

I've had a handful of two-girl adventures.  It's always risky because it depends completely on the chemistry between the girls.  As mentioned, if they play tag-team, its not very exciting.  But if its a real three-way, then its an extreme turn-on.