I had to do a little playing around with them, but got them crisp the second time around. I cut them to thick the first time, but then too thin the second time.
I have a nice mandolin slicer. 1/4" too thick, 1/8" too thin. Right in the middle (3/16?) just right.
Single layer at 115 F for 12-ish hours.
I've had them come out crisp, then I stored them in a ziplock bag and they got limp on me. I redid them for 4 more hours, and they stayed crisp.
I oven canned the chips one year and they kept for as long as it took us to eat them all...not a year...ONLY because we ate them.
I make a BBQ seasoning with finely ground sea salt, sweet paprika, smoked paprika, garlic powder (and if I don't plan on oven canning them, I put a pinch of sugar to it. I don't have measurements, just add by sight to what I like. I run it for 10-15 seconds in the coffee grinder to make sure it's finely ground.
Before I dehydrate, I salt my slices and let them drain in the sink for a few hours, then rinse them. Keep that in mind when you add your salt to the sprinkling mix. I lay them out single layer on the trays and then I sprinkle the mixture on them, then process them.
USDA Zone 7b/ Sunset Zone 31