re: twohots
Sounds like we have similar types of friends ;-) A large part of the ratio has a lot to do with the male halves of couples. I have seen guys that can play with a half dozen women at a party (usually some of the married ones) and others are there solely to watch their female half play, and everything in between. Most guy heavy parties we attend are closer to 2 to 1, but most of our regular crowd can easily handle 3 to 1.
The other factor is not all guys are comfortable sharing a women. I personally love it as long as that is something the girl is looking for. We've also seen cases were women prefer to be 1 on 1. They certainly have the option open to them but find it more distracting than pleasing. We try to do onto others as they want to be done onto ;-)