I ran a small Crockpot kiln for a couple of years using both a remote hygrometer and an 8 oz. cup of rock salt. The RH pretty much remained at 75%. The remote hygrometer finally gave out from the kiln temps, and I didn't replace it. Once I recognized that mold just won't grow at 125ºF, I gave up on the salt as well.
Currently, I just run my kiln at 120-125º, replenish the Crockpot water when it runs out, and watch the calendar.
With my kiln (the endoskeletal kiln) running in my enclosed back porch, I am always treated to the wonderful aroma of warm tobacco. Also, my curing shed smells like weeds when I first start housing green leaf, but once some of it has begun to color, the aroma grows more and more inviting.
Bob