This is what I have been using for the past seven-eight months and it work's very well. I use this system for re-hydrating dry tobacco as well as (and mostly) for keeping "fresh" the tins I have opened and I am currently smoking. I wish I had thought about it earlier, I would have saved a lot of half full tobacco tins that I had ended up trowing away.
It consists in a small cigar humidor that I had dismissed, a Cigar Oasis humidifier, and a bluetooth hygrometer. With the bluetooth hygrometer I do not have to open the humidor to check the humidity, I can do it directly with my phone, but it also keeps the records of temperature and humidity for 30 days.
If I have to rehydrate I start low, usually at about 65% and then I progressively increase the humidity to the right level, which for the tobaccos I generally smoke is within 76%-79%. For comparison cigars typically need 67%-70%.
I rarely smoke anything with Latakia or heavily flavored tobacco, if I did I would use a dedicated humidor.
By the way, the humidor may help but I don't think it is absolutely necessary, a box with a good seal should work as well if something like the Oasis is used, instead of passive humidifying elements.
The Oasis is good at controlling the humidity is such a small humidor. Here are a couple of charts that I took when I was still experimenting:
This one is of this evening after I took some tobacco to smoke: