Mmmmmm..... heating of the mixture DOES play into detonation and a lot of that heat comes from the head. I came across a research article recently that found that a hotter mix burned more slowly. A more extended burn time (like with open chambers or large recesses or the plug waaaay off to the side) is a known contributor to detonation tendencies, due to the longer burn times.
So anything that lowers heat transfer to the mixture in the chamber should help. That includes being AL instead of iron with the lower thermal resistance and lower chamber surface temps. Not wanting to be disrespectful at all, but the idea that it not been proven does not seem (to me) to hold water; the general experience with AL heads all points that way. IMHO, the same applies for polished chambers: less heat transfer to the mixture.....less tendency to detonate.
