Wish I could help, we won't be there at that time.
I did this with another family back in Feb. I would suggest you add the date and something like "want to share" into your header. Also, if you have not already done so, post it on the Cruise share thread.
Good luck
PS. Not sure exactly how much you are willing to spend, but since you say you are willing to pay for "mist of the other party", you could call give kids the world, donate the 4 spots to them, do a good deed andtake a tax deduction/