I'm inclined to think that going to an organized event is your best option.
As a couple, we're pretty weary of single women who answer our ad. I guess we've been so convinced that single women are so hard to find that we assume most single women online are actually male picture hunters. At a meet and greet or an off premise club or something like that you and your prospective partners can see that you are who you say you are. Furthermore, there is some security in these events as there are more people around. I don't know about you, but I can't think of anyone I might want to bring on a date with a couple (or single) if I were a single woman looking for swing partners.
Furthermore, I wouldn't discount the idea of getting some group sex action going on with people you already know/date. Of course this idea does carry both pros and cons that have been discussed at length elsewhere on this board. It's not an impossible idea.
Good luck you and keep in mind ES's advice,
"Lastly, don't be so cautious this becomes work." (along with the rest of what's been said here. I agree with all of it - except for the buy a gun bit
)