I have tried all of these methods and my conclusion is there is no perfect solution. When I booked my upcoming trip I had one couple confirmed and they said they had a second couple. I booked the charter during a week that fit their schedule not mine. The day I booked I get a call that the "other" couple is out. A month later the first couple filed for divorce. I also held off booking until very late because the first couple lost his job and I waited until he found another. After several months of contacting every friend I have to get a second couple, even offering the trip for free, I finally found one. I told them they can go for free but have to get their personal expenses, flights and boat expenses. They are vegans so the provisioning has been a pain in the a@@. My friend getting divorced found a date but now I have to pick her up 2 days into the charter, rearranging schedules. Not to mention, our week is now Christmas in July. The first couple wants to eat out every day, the vegans want to eat on the boat every meal. I sent out a 30 page extremely detailed guide I spent hours putting together. Everything from tying knots to what clothes to bring, itinerary, pictures and video of the boat, you name it! I am 23 days out and still getting questions like how much are we going to sail? It's a power cat. Oh it's a catamaran? Do we have to get water taxis if we want to go ashore? No, we have a dingy! My point is that it DOES NOT MATTER how firm and clear you are with money deadlines or anything else, they won't care or take the time to read or listen. It's infuriating to me that I put in so much time planning and taking care of every single detail, all they have to do is set their alarm clock to go to the airport and no respect or consideration is given. Man keeping a spreadsheet??? That seems like a nightmare! I told my crew they can send me a check for the remaining expenses ahead of the trip to make saving/budgeting easier on them or they can hand me cash when we are at the STT airport or step on the boat but it's not leaving the dock with them on it until all money is in my hand. I am determined to find better friends or a better system next year.