What a devastating blow Oz. Sorry to hear. Seems many have different lessons to learn, and sadly many are the hard way. Must be hard trying to be so involved remotely too. I am sure Team Bernie is doing his best given the resources he has on site.
As for humidity, how wet is too wet in the eggtopsies? We try keep our humidity 50-55% and have not had any drownings or wet air cells yet. I am not sure how wet they should be at what stage. Maybe you could look into weighing of eggs to monitor the right humidity oppose to just relying on the figure? It is a little more work initially, but coupled with the humidity reading you should find a happy medium to 'set and forget' later.
Best of luck, will keep our fingers crossed for you and the team. Adversities, if we didn't have them it would be too easy and everyone would be doing it.