I've got six of these exact 70qt coolers.
- Yes, they are full

They work well but you will find that some seal better than others.
I tried the lid/fit on all of them before I bought the ones that had the best fit.
On the lid there is a small groove/recess that will allow you to put a gasket in the groove.
Walmart sells a self-adheasive rubber "D" gasket 3/8" x 5/16" found in the paint supplies dept.
Fits perfect in the groove!
Suggestion-
I used the GIANT Ziploc Big Bags "Large" size inside the coolers.
(The XL and the XXL Ziploc bags are just too big)
You can get a few boxes (3-4 boxes) inside the bags, then put a 1-oz (or 2 1-oz) bead tube(s) in the bag.
Then into the cooler.
This way, when you open the cooler lid you don't lose the RH in the whole storage system.
The cooler keeps the boxes from big temp swings.
The individual bags keep the boxes from big RH swings.
I also installed a Xikar digital hygrometer in the lid of each cooler.
- More to monitor temp rather than RH (trust your beads).
Works great!
I also keep a number of desktop humis for the sticks that I smoke regularly so that I'm not playing Tetris any more than necessary. LOL