Alex, I think there should be a "plan B" as well, based on a smaller number of takers.
I have been involved in making these sorts of arrangements for an Internet group in the past, with decidedly mixed results. ( I did, however, find my dear wife in the process!! ;-) )
If it's solely dependent on getting 15 or 20 takers, it might end up busting out.
I got an Old Fat Boat
She's Slow But Handsome
Hard In The Chine, but Soft In The Transom
I Love Her Well, And She Must Love Me
But I think It's Only For My Money
. ..... Gordon Bok