can i use any varites of sweet potato, type of oil,baking time,sensory properties??????

Yes, you could use this recipe with different varieties of sweet potatoes, and in the article (http://food52.com/blog/8842-homemade-sweet-potato-chips) for this recipe, Laura explains why she recommends grapeseed oil: "Lastly, a neutral and high heat-tolerant oil makes a huge difference. The big brands tent to utilize canola oil for frying, which seems to make for an “oily” tasting chip to me. I want the purity of the sweet potato and whatever spices I'm using (full disclosure: I used taco seasoning) to come through; grapeseed oil is my first choice for this. A cinnamon or chai-spiced chip might benefit from a splash of coconut oil. "

The chips are baked for 18 minutes and flipped at the halfway point, you're looking for them to be lightly golden brown with a tiny bit of give in the center.