[Barnsnake]

I definitely feel you would be better off with forgings.
Detonation is functionally equivalent to hitting the piston crown with a sledgehammer. Sometimes it will break the piston crown down to the top ring land (as in your case) and it sometimes knocks the skirt completely off the piston.
As noted, aluminum pistons are alloyed with silicon. The higher the silicon content the lower the rate of thermal expansion, but they become increasingly brittle as the silicon content goes up. In an engine that might experience non-progressive combustion, this brittleness is a risk.
Alloys with high silicon content cannot be successfully forged since they are no longer malleable. That is why forged pistons require a looser cold fit and audible piston slap sometimes occurs until they warm up. The payback is the "toughness" and resilience of the lower-silicon-content forged pistons. I've seen them hammered so hard by detonation that the ring lands are bent down far enough to pinch the rings, but nothing "broke".
Detonation and pre-ignition are evils to be avoided, but the forged pistons give you a little more room for error.