Boveda is absolutely the way to go. They actually regulate in both directions, so a 65% pack will pull moisture exceeding that, or release moisture in an environment that's under 65%. Boveda themselves recommend one of the larger 60g packs for every 25 cigars, which I would also recommend depending on the container. A wooden humidor probably needs 60g of Boveda for every 25 sticks and might still "dry up" fairly regularly, especially if it's not full of cigars. The less cigars you have in a cedar box, the more moisture you'll need to keep conditions stable.
I use Coleman coolers for long-term storage, as they are mostly air-tight and more importantly, they do a better job of keeping wild temperature swings here in the southeast from messing up my stash. Relative humidity can fluctuate quite a bit without many issues (from high 50s to mid 70s), but high temperatures can cause beetles and that's no good. Colder is better, as far as temperature is concerned and it gets damn hot here for 8 months out of the year.
Anyhow, I've got several coolers but my biggest probably has 1,000 sticks in it, mostly in boxes, and I only have about a dozen 60g Boveda packs in there, not 40. And I only have to change them once per year. Humidity is constant in the mid-to-high 60s.