I have never sold any green, always dry mine and wait for the price to peak (usually does around Thanksgiving). But then I don't need the money quick so I am fine with waiting for the price to peak.
After washing my roots I towell dry them and then spread them out on a window screen and just leave them be until I sell them. It takes 4-5 weeks, with larger thicker roots going 5 or more to dry them like that, but like I said, no hurry so I just let them dry like that.
I keep them in a room, inside, low humidity, air conditioned, etc... and they dry nicely, and retain good color inside and out.
I hear that \"sun\" drying roots or drying them too fast with to much heat, can cause bad color inside or out and seriously decrease your seng value.
A dehumidifier I am sure would be fine, but I would not dry mine in the sun, not exposed to direct sunlight.
If I needed to dry some quick, I would do something like spread them out on a window screen thinly, and put them in a inside room, with a dehumidifyer, and a small room forced air heater with the heat set to 80 degrees or so. I would not go any hotter than that.