it's tough to know from a picture if that pizza rack is stainless, aluminium, or just chromed steel (might be hard even in person, especially if it's from china). If it's the first 2 you shouldn't see any rust. and they'd work just fine (Just boil the aluminum one in water for a bit. I'd BKF the rack and then leave it in water for a bit, take it out and let it dry over night. if it's rusty I'd guess it's just chromed steel. and I'd find an alternative.
Great idea! Even if it doesn't work out as planned. good luck