So, back when I was active here I got to where I pushed Boveda like they were crack. Main reason is because they took the worry, the constant watch and wait out of it for me.
Don't fret at every single hygrometer reading you see. They are never going to be 100% accurate all the time, no matter what hygrometer you get or how much it costs. The faster they update readings, the more they will seem to be off - especially if you're a fan of opening and closing the cooler to appreciate or often remove cigars. Each time you open, that outside humidity is going to blend in some. Not enough to throw everything off, but maybe a reading when it hits the air. I don't speak for anyone else, but I refuse to put a hygrometer in my tupperware anymore. Just no need, because all it did was caused worry. I trust the Boveda enough that I don't feel I need them. I can judge when it may be time to swap or move Boveda around, and do that as might be necessary but to sit and watch a digital readout is only going to cause stress.
If you think you have enough Boveda? Add three or four more. They can lay anywhere, don't take up much room..and you cannot over do them. If you stay steady, your Boveda should really NEVER get that flat grainy feeling mentioned above. I've been using the same packs for five years, and never really "HAD" to recharge or replace them. If you do have some that dry out - don't throw them away, recharge them.
If they are over swelling or feel about to "pop" they are working way too hard, and you definitely need more. Don't throw them out or replace them, just add some more to stop them working so hard and spread the love around.
To each their own, and some may disagree..my own personal taste is. You don't need the boxes or trays. Anything cedar, wood of any type really..is going to absorb and release moisture at varying rates. It is also going to release it if the outside air isn't as saturated. It's a great buffer when well seasoned in a wooden environment, but you're storing in plastic. You take up a bit of room with wood storage vs plastic smaller dividers or containers. You're going to affect the entire humidity a ton less with the plastic and boveda combination. The only time I'd consider keeping boxes is with special edition releases, coffins and things like that.
One last thing. Might shoot for 62% Bovedas. That's all I use, on everything. No product is perfect. There will be some times you're running Boveda and may read 68 if you're using 65. It doesn't mean your humidity is always at 68. Or that they aren't working, or that the cigars will be too wet and bad. Just that when you checked, your hygrometer said 68. It may only read that way for a short while. Might be sitting next to some newly bought, wet cigars. Maybe right next to a Boveda pack that is pulling moisture out. It doesn't just happen with the snap of a finger, bigger the space the longer the time to regulate.