Well, they're in.
Verdict - much, much tighter, punchier, more growl in the low mids, accentuates pick attack nicely without sticking a knife in your ears, smoother high end, much less fizz, fuller tone, and much thicker but nothing is lost in clarity (if anything theres more due to the tightness and chainsaw-yness now being gone from the top end.
I didnt get the sound in my head out of them, I still need to find some valhallatone unobtanium 600s going for a decent price second hand, or catch a demon, but its a couple of steps closer and certainly a big improvment in the direction I wanted.
Thanks for your help guys, especially antag and roo. Your advice was spot on - these things are doing what you said they would.
Edit - I'm eager to hear what these sound like burned in.
Should enhance the lows and mids rather a bit.
