Hi Woof,
I do mine in the microwave and finish for about five minute in a very hot over after rubbing them with oil and they are almost as good as those baked completely in the oven. So not too long.
Wouldn't it be cheaper to oven bake a batch of them when you have the oven on for something else and then freeze them.
Having said that I buy the McCains Rustic chips with skins on and they are yummy and only 30% fat. We all need quick food at times (and I don't like proper home cooked chips anyway)