Honestly, the amp sim is the smallest part of it , and that limitation is easy to remove: NAM (Neural Amp Modeler) is free, and Tone3000 is full of free captures. I run NAM Gateway with a 5150 and a VH4 capture from there and never look for anything else.
The wall comes from three things, none of them the amp:
- Double-tracking. Two separate takes of the same part, hard panned L and R. Not a duplicated track nudged in time , an actual second performance. The small differences between the takes are the width.
- Less gain per track than feels right. Gain stacks when you layer, so two tracks at moderate gain sound bigger and tighter than two maxed out. Both maxed just turns to mush in the middle.
- Different IRs on the two sides, and a high-pass around 80–100 Hz on each. The weight isn't in the guitars, it's in what sits under them, if the guitars keep their own low end there's nothing left for it.
And on my end the wall isn't only guitars. A good part of the weight is synth: I use Omnisphere for the bass and for dark ambient layers behind the riff, and that's what pushes it towards industrial rather than just loud. The bass is often a pure sine at the bottom, layered with something richer on top , the sine alone has no harmonics, so on phones and small speakers it disappears; the upper layers are what make it audible there while the sine carries the actual weight. The plugin doesn't matter, Vital and Surge are free and do the same job. The principle is that the guitars carry the mids and the attack, and something else carries the size.
No muting homework from me. The only honest catch with doubling is that two loose takes panned hard sound twice as loose, so it's worth tracking in short sections instead of full passes.