I looked at all those plans last year, then realised that they boiled down to an electric fan oven set very low. Which I have.
So I have masses of apple rings dried over night in the fan oven. This year, I will dehydrate more things, as the apples were so successful. We have one of those gadgets that show how much electricity you are using, and the fan oven, set to fan only, or minimum heat, is very economical.