Lots of things on a 6-8 week charter could mean " not sleeping soundly". At least for someone in your party--
AC is not a deal breaker. Where you moor or anchor has a lot to do with how much breeze you will catch, and the configuration of the boat you charter will make a difference in how ventilation happens below deck and through the cabins.
There is no rule that you have to sleep IN a cabin below deck. Take a pillow and a sheet and settle in wherever you like. Under the Bimini, you may never know that it is even raining.
Your vacation, your money. AC and gen-set are two systems that you really need to understand before you charter, and both of those systems are the cause of most requests for chase-boat service and repair while on charter.
A charter boat is not a floating hotel room.