I live in Arkansas so I fully understand when it comes to heat and humidity. It's like Satan has his ass crack sitting on Earth.
My personal opinion is your HVAC should do more than enough to suck up any excess humidity in your house, unless we're talking about a basement. You could always run a window unit in that room with door closed I guess if you were worried about it.
Temp of 74-77 should be fine
IMO.
I have had the bulk of my gaming and comic collection in a conditioned storage unit for over a year that runs an ambient temp of 78-80. Last time I went by there and opened a few boxes everything looked fine.