My first thought when I saw this thread, totally without any justification on my part, was "Here we go again - another "Global Eagle" escapade but in a different guise" !
Already questions are being asked about the actual challenge - disputing current records, how much of any donation will actually get to the "charity", is the charity a worthy cause etc etc....
It just shows how much damage can be caused by a previous and ill fated expedition like that of the Global Eagle farce, to have prejuduced my views in this way.
Prejudices aside, and assuming this to be a genuine record attempt / charity fundraiser, then good luck to the team
You might like to check out the Global Eagle thread before you set off, to give you an idea of the some of the challenges and potential criticisms that may come your way if everything doesn't go according to plan :
Global Eagle
( Allow an hour or so to read it all from the beginning if you haven't checked it out before ! )