preheating, oiling, sticking, etc.

I have a decent gas grill - actually my first that is not a cheap piece of junk. I am struggling to adapt to the amount of heat it puts out. The grates are thick round metal rods. I am having a lot of problems with meat sticking and then ripping apart and leaving chunks behind when trying to move it. This concept of the meat releasing when it is time to flip it - I don't see that happening. Also a tendency to overcook the outside and undercook the inside of things (salmon, pork, chicken, beef). I generally try to wipe the hot grates with some olive oil on paper towel before cooking but I feel like it is just burning off. I get the grates well-cleaned, they are not covered with gunk.

Cook's Illustrated says this about getting ready: "Turn all burners to high, cover, and heat grill until hot, about 15 minutes. Leave primary burner on high and turn off other burner(s). Clean and oil cooking grate."

After 15 minutes on high, this grill is nearly 900 degrees, and the oil instantly vanishes in smoke. It is hard to believe that is accomplishing anything.

Your thoughts?