69% is probably better for a wood humidor, I like my cigars a little on the drier side so I go with 65%.
I would get 2 packs, they will last longer and do a better job of recovering after you open the lid, plus there's no harm in putting too many.
I've never used the seasoning pack for my desktop, you can certainly go that way....I'm sure other's can tell you how to do it. I just put a dish of distilled water in there and kept the lid closed for a week or so to let all the wood inside absorb the water slowly. Once it is saturated (consistently over 80% for a few days), I take the dish out. Then check daily, once humidity gets down to about 70%, put your 69% boveda packs in. If it's holding around 69% (+/- 1%) for a couple days, then put your sticks in. The seasoning process should take about 2 weeks, there's no shortcut here. Get yourself a reliable digital hygrometer too, this is key.