Stopping the knock: Lower compression and ported heads...

I thought the same thing.
I am not married to any one "fix". If the thicker gaskets work, I'm cool with that. If the thinner ones work, I'm okay there too.
One of the most frustrating things for me is when I do a teardown and can't find any obvious problems. I read before that on a detonating engine, you'll see speckled deposits on the spark plugs. I didn't see any of that either. If what I was hearing was NOT detonation, what was happening? The LH header was close to the steering chuck and may have touched a few times, but I doubt that would have gone away when I was burning the 110 fuel.