@taxlady I dry them (on parchment with nothing on them) until they are crisp and completely dry for storing at room temperature.
I dry them at about 125 deg F, for many many hours sometimes a whole 24 hours depending on the thickness of the slices.
If what you are looking for is a pliable dry tomato slice, then only dry until they feel just right, I can only guess at the time, 12 hours. Then keep them frozen so they don't rot or ferment.
How to test. For complete dryness, they need to cool completely to room temperature, put them in a jar, shake them daily for a week and they should rattle hard against the jar. If they get soft then they need to go back in the dehydrator. It's called conditioning. (the moister portions of the slice give off some moisture and the harder parts suck up moisture until everything is at the same moisture level)
For a softer pliable slice, cool to room temperature, check for pliability. Once you are happy with it, keep it in the freezer.