I was just asked the question why 15?
I have done this trip with 6 and that was considered a good manageable number. Trying to get a lot people into places like Chambers Pillar, Palm Valley, Lambert's Centre etc would be a nightmare if there was 20 to 30 of us, even 15 will be a challenge in some spots.
Furthermore, everything just takes longer the bigger group you have. Getting through a set of traffic lights with that many vehicles with campers can take ages. Statistically too, the bigger the number, the more problems there could be (mechanical) which also takes up time. You have to expect one every now and then, however if that becomes two or three in the same day we will get no where.
Also, the gap between the first and last vehicle would be so large that they would be out of UHF range in some places when we are travelling on dusty roads, and that would mean relaying messages and just a general PITA.
Finally, when checking into the paid campsites, the first few will be all set up and finished off two beers by the time the last person even makes it in the reception door.
So what I am really trying to say that as the organiser, I would like this to be a holiday for me too, and not a 16 day logistical nightmare where all I'm doing is stressing about how I am going to coordinate so many 4wds with camper trailers.
Believe me, I would like to take 50, but it is just not feasible or practical.