Amp settings

That depends, is this just raw amp or are you running anything through the front like fuzz, overdrive, or distortion?

For the really sludgy stuff you may need something else to help push the signal where you want it. I own an Orange Micro Dark and unless I crank it up really high it sounds best with something like a Big Muff or an oversaturated Iron Horse v2 to get it where I personally like it. Realistically you just have to play around until you find the sweet spot, because the pickups and speakers you're using are going to influence how that particular sound actually hits the room.

so that is a hybrid design, with a single 12ax7 preamp and a 20w solid state power section. normally maxing out your gain and volume, boosting bass and mids, while kind of taming your treble is how you would achieve a "typical" doom sound (in your case I am a little unfamiliar with the shape knob but if I recall its a Bax tone stack on dual potentiometer , turning it clockwise increases treble and bass but lowers mids, and counter-clockwise increases mids but lowers treble and bass). However, with that having a solid state poweramp, the tone that comes from a solid state poweramp isn't always desirable compared to a tube poweramp. It has to do with the way tubes vs transistors clip. With that being said, you have probably seen the Sunn Beta Lead being an amazing doom solid state amp, so YMMV. I do recommend turning up the gain to where its clean when strumming normal but starts to distort when strumming hard or aggressively and throwing a fuzz pedal before that while keeping your poweramp clean (leaving the volume at a normal average level), that's typically the angle I go for. Ultimately its your tone to sculpt, good luck on your search!

I suggest you use your ears. A good way to start out is to get someone to play your guitar while you fiddle with the controls, 2 at a time to get the sense for their interaction. Volume is probably least interactive as it's probably a little class d amp at this size that imparts little to no tonal footprint.... spend time with it. You'll find the sound you want and a lot of other tones too.

You must listen to the correct time. :-D Let your ears be your DeLorean!