Spark plug reading?

I find Autolites seem to last the best, and they are easier to read than Champions for me. The "best choice" in terms of reading are the NGK Race plugs. A little more money, but I like tham in something that has to make power. What I see, is you need to replace them after you warm up the engine, then drive it, and then look at them. They've got too much carbon and soot on the rings to be of much use.