Did Scotty get a new job or something? he's usually right on top of this stuff.

Here's what I know based on what I've learned here:
Copper over Iridiums because of cost. Lots of guys are changing gaps and heat ranges trying to kill KR. If you try a set of coppers and they don't work so well, it's not a huge loss. I have iridiums (one range colder than stock) and they work fine. They also came gaped at the factory spec 0.060" I check the gap on every plug before installation.
No platinums. Our ignition system eats them. Something about the waste spark system? IDK.

If I'm wrong on any of this, someone will correct me.