Reminds me a bit of Thomas Gatch. Interesting but tragic story:
https://en.wikipedia.org/wiki/Light_Heart_(balloon)
He was last seen by a freighter thousands of miles off course, with his balloons damaged....he made no effort to signal the ship for help, and experts think he may have already been dead at the time of the last sighting.
The important things will be to make sure the balloons stay on course, and provide contingencies to prevent deflation.