Moisture meter is to measure the moisture content of the plant in the stem. It's more accurate for the timing of placing the bud in the bag. There will still be residual moisture in the stem of your bud go out to the rest of the bud for proper moisture to the entire bud. This should result in the relative humidity being close to the optimal 62% relative humidity The hydrometer may show a lower humidity the first day or so, but the moisture in the stems will migrate outwards and raise the relative humidity, so don't do anything for a couple days, unless it's higher that 62 right off the bat. The hydrometer is there to confirm the relative humidity and to let you know if you need to burp. Once it's stable for a week, I'd say it's good to seal. I did this in big bags and once it was stable, I re-packaged in half oz bags and sealed them.
The idea is to test the stem moisture level and bag at 12% and burp until 62% is achieved. I'd not add any packs unless after waiting a few days after bagging, the Rh didn't come up. Grove bags says he'd rather you not put packs in the bags, but I don't see how it hurts in that situation, as long as you remove it once stable.
