The Screamin Demon reminded me something like how a Custom Custom is thick and fat sounding compared to say a Custom 5.
Actually, I would say the SD I have sounded similar to the CC with the thick lows and mids, but tighter. I liked it better to be honest.
At least in my all mahogany BC Rich neck thru Beast.
I've also been curious about trying the Pearly Gates Plus in the neck position.
I guess what I'm searching for is something between the 59 or Sentient neck, and the Distortion neck.
Something with some bite and harmonics, but that stays extra tight in the low end.