We recently got a new grill with porcelain-enamled cast iron grates. I read a few places about oiling and "seasoning" the grates. I don't think I used enough oil during the seasoning phase (oil grates and cook for 2 hours on medium). On first use I heated the grill and oiled again prior to putting the food on (chicken breasts). Sure enough, got some sticking. Did a pork tenderloin last night with little better success (used a lot more oil). Any secrets/advice on keeping things from sticking? I feel like I am always battling this issue.