I've been using the Helix for about 2 years now. At rehearsal, I've experimented with both IR's or using my Legacy 2x12. While there are pros and cons to each, i prefer running the cab at rehearsal. However, I prefer the IR's for recording because it gives me more options than I have cabs or mics.
I've found some pretty brutal modern high gain tones, and it's based on some simple concepts that also work in the real world with the actual gear.
My typical recording chain looks like this:
[Screem 808]
Overdrive=1 to 5 *I tend to stay around 3
Tone=5 to 7 *depending on what style you're playing in, you may want to have a little more bite or a little less.
Level=10 *helps drive the front end of the amp **the soft clipping keeps tone intelligible and the 808 takes a little bottom away which can be over accentuated in high gain tones
>[Modulation FX]
>[Delay]
>[Brit2204]
Gain=3 to 6 *because you're driving the front end of the amp with a pedal, you don't need as much gain from the "gain circuits" in the amp.
Master=5 to 8 *this get's the cool parts of a tube amp operating. IRL, I start to dial in a tone with the gain on any amp at like 2, then set the master volume to something appropriate, then dial in gain to taste
otherwise all stock
>[Ownhammer MR82 IR]
>[Parametric EQ]
Freq=3000hz To 4000hz *find the painful noise and remove a bit of that; Q:2 to 5; Level:-2db to -6db
I also have a very similar chain for the PVPanama.