Boveda will never humidify beyond the RH on the pack, so there's no such thing as "too much". You want to think in terms of using at least the minimum because the more you use, the more efficient Boveda works and the longer they last
67 gram Boveda are commonly used in mason jars and large bags. They can last 6+ months depending on how often the container is opened, you'll know it's time to replace when the entire Boveda begins turning hard.
Boveda provides the cleanest and most purified humidity of all other products available on the market today.