Incidentally, everyone should print out and frame the diagram on pages 15 and 16 of that. At 117 pages, the whole thing is going to have to wait for some night wen I'm the last one in the office, but...
Reading it, I suppose I should probably stop rolling off everything below 120-200hz on my rhythm guitars by default...

Leads, sure... but for heavy rhythm it seems I've been screwing up all these years.