The too wet, too dry tobacco issue is solved at my house by the use of an inexpensive cigar humidor. ($50).
I store my rotation of tobaccos in a small humidor with the cans open. This provides a 70% relative level and a fine smoke. I know there may be a mixing of the tobacco flavors so I wouldn't store aromatics with other tobaccos. As I smoke predominatly English blends or flakes a slight mixing is of no concern to me.
Humidors are available in several sizes, mine is a "50 cigar" size and holds about 8 tins of tobacco.