The Little Rock ain't high gain unless you use pedals. Also, the extra pre-amp stage sounds fizzy unless you crank the master. That makes it quite loud for home/bedroom use.
I'm finding I only use the clean channel on mine. To get good drive at low volumes (Thin Lizzy, Guns N Roses, Foo Fighters etc) I'm using pedals:
Guitar -> Maxon OD-9 (tubescreamer) -> Treble Twister (booster) -> clean channel on max, lowish master volume
I also use Metal Muff if I want Sabbath/Ozzy levels of dirt, in place of the OD-9.
For what you want, I'd get a good tube amp and pedal(s). I doubt you'll find a good low volume 'metal' amp where you can use the tube preamp without it sounding fizzy and scratchy (unless the Engl is good at those levels?).