Cool that this thread is still going. After more time spent on metal toneage I've found that the amp does indeed make the most difference. So much flavor comes just from the amp. Which I know folks have repeated ad nauseum, but that's what I'm finding as well. For me it's turning out to be the 5150 sound that I love, and then just tweak EQ/boost/compression to taste. Hex head polepieces help with tightness. But through that amp (well, through my preset on the Fractal FM3) I'm getting satisfying metal chunk from all 6 of my guitars (each with low-medium output pickups). And honestly there isn't a ton of difference between the sound of the guitars at that level of distortion.
I will add - I'm liking having an overdrive metal tone and a high gain metal tone on tap. One is pretty guaranteed to scratch the itch as a bedroom/studio player.