I have several pieces of cast iron that need re-seasoned because I didn't do it properly the first time. I put too much oil in thinking it would speed the process up, Only created a thick layer that didn't adhere well and came off in places. Started cleaning it off by hand, slow, tiresome process. I think I'll try the 600* method, pick up some flax oil and try again. I love cooking on good cast iron and the food seams to taste better also.
I just worry about warping anything. I looked over everything good and mine stuff came out with no warping. I had the covers laying flat on the grill and the DOs leaning up on them. This time i have the covers on top just sitting off to the side. The covers that the oil burned off were really dry like when you self clean your oven. You could feel them taking in the oil.