Two years ago, my GF went to Bonaire as part of a 30 folks gaggle. It did not take long for the group to split into similar affinities sub groups (experience level, maturity level, chemistry, etc.)
Last year, we literally built a group of initially 18 for a week on Blackbeard. Interestingly enough, we got the folks to meet and dive a couple times before we ended up packed altogether as a big family for a full week on a 65 ft sailboat and very little privacy. All was fine until somebody punched out at the 11th hour (I will revisit this one). Blackbeard provided a replacement, 40 something experienced Spaniard diver who got teamed up with one of my friend who is learning Spanish....and we had a great week. Not so for the other boat which ended up with 22 folks travelling as separate singles and couples and their trip was not as enjoyable based on the comments that I heard back in Nassau.
This year, we are organizing a two week diving trip to Bonaire that will take place in Feb 2012. 10 folks max as this is the maximum number of folks we had in mind and it is also what the villa will accommodate. Not necessarily easy to find 10 folks who all have similar skills and experience, get along well, all have time off and want to spend two weeks at a time. So we have a solid core of seven and some electrons that are still gravitating around and have not committed yet.
Lessons learned...probably next trip we plan will be the hardcore individuals of our group. Not in terms of Extreme diving but folks who do enjoy diving, are great to be around, have no fear to commit and will remain committed ie not punched out at the last minute. This is probably the most frustrating part of being a volunteer organizer who does it just for the fun of it and with no fringe benefits except the great company we end up with and the diving of course.
What I do in between...diving trips of two with my GF. Very easy to coord and enjoyable...until you meet a group of 46 (30 something divers) at the airport not only going to the same destination but also residing at the same hotel and once there behaving like they own the place...and the boats.