What about gauze or muslin on the rack?
I noticed on some websites a concern that placing the SP on a metal pan did not allow the air to circulate around them well enough (even with turning) to dry effectively. I was wondering - since the oven is only at 250F, could you not stretch gauze or muslin over the rack (& safety pin if necessary) and dry the slices directly on the fabric covered racks?
OR - I bake pies in paper bags because the crust is so much flakier and my oven stays clean. What about a single layer of paper directly on the racks?
Would either method help with the drying?
Chef's Answer ~ Wow, those are great ideas. I don't see why they wouldn't work! :) Another idea would be to put a wire rack on top of the baking sheet and then place the slices on top.
But you may not need to take these extra steps. I would recommend trying the recipe the way it is and see if you have a problem drying them. I personally live in a humid environment and I did not have any trouble getting the sweet potatoes to dry.
If you use the methods you mentioned, please come back and let us know how it went! :)