Hi Lowlandtrees,
Dampits will add unwanted wet areas to your bass which could open up old cracks
I`ve been shipping basses with Boveda packs, they are also useful for daily use if you pack one with your bass in it`s case. It will create a microclimate
My good friend Nick Lloyd demonstrates here how they can be used to stabilise humidity.
Humidity, Boveda packs, and your bass. - YouTube
Best Wishes
Martin