Flirting/Attraction/Interest

So the wife & I attended an event last weekend and had an awesome time.  We met a bunch of great couples and throughout the evening narrowed down our attractions to two couples.  We had engaged in small talk with these couples throughout the evening so we decided to attempt to "corner" each couple and gauge the attraction of each couple through conversation and flirting. 

Couple A
A great song came on and we enticed them out to the dance floor.  The wife and I danced together and then traded off.  Things were pretty heated on the dance floor, so we were able to seductively dance for a while, butt squeezes were exchanged and plenty of rubbing together ensued between each couple.  We thanked them for the dance, chatted for a bit and exchanged info.

Couple B
We noticed this couple early on in the night and had traded many glances.   As the wife & I were walking around later, we noticed them sitting at a table and asked if we could join them.  We engaged in good conversation with them, both of us flirted with them through playful words as well as some incidental touching however it seemed they were not interested in reciprocating so we thanked them for the conversation and moved on.

Later in the week I received a message from the male half of Couple A asking if we had a good time at the party, etc.  We chatted back and forth for awhile, shared some sexy pic's, etc.  I asked him if the two of them would be interested in drinks/dinner/date and this was his response, "Well the wife is not really into the lifestyle right now, but is letting me play on my own."  Say what?  She engages in seductive dancing with me, then i get this?  I checked their profile pic's and it was the same woman.  Hold it, they have a profile as a couple yet she doesn't play?  WTF!  Needless to say, they are a NO.

Our interest level in Couple B was pretty high, so we did some stalking on SLS and found their ID.  Sent off a message and instantly got a reply thanking us for reaching out to them.  We exchanged KIK info and have been chatting with them for a few days now.  We still are unsure of their interest level as conversation has been pretty vanilla.  Most of the chatting has been between the males.  Hopefully, we can move this in the right direction.....

Questions and Conversation
How much attraction and flirting do you do with a couple before you "give up", whether it be at an event, party or online?
Do you ask another couple if they are interested right away, gauge it, or just ride it out?