I recommend watching the full video to every recording guitarist, but here I linked the 'eq trick' which I also use a lot to shape my cab/IR tone.
definitely one of those things that is easy to go overboard on if you listen loud and in isolation. I think often 2-3dB can be enough, and only one or 2 cuts to the most prominent areas can be plenty (as Zach mentions he does). Tight Q, deep notches, lots of EQ moves=phasey mess, if you aren't careful.
Very context dependent on how much gain there is, what the parts are doing, what other parts are playing at the same time, what other instruments are playing etc. I don't actually mind some limitations with EQ because it forces you to focus on the biggest problems and it helps stop you overdoing things when changing the IR or settings a bit would be more effective. For guitar tones, its arguably more valuable in a mix context after the fact when you can assess whats going on, rather than in a "performance" scenario where things might be out of your control and someone else further down the line would be better placed to EQ.
(Not that I use them, but) There are some guitar focused plugins that have a single notch band as well as filters and (analog style) shelving bands. I could imagine something like that being useful where you have things pre-mapped a little, and saves you having to choose filter types and Q values and things. For only guitar processing, I could probably live with:
- a single notch band
- HP and LP (12dB/octave or 18dB/octave)
- 10k high shelf (something like API/Neve/Helios/SSL style)
- low shelf (maybe more Neve/Pultec style where there is a little overshoot so frequencies above the boost get dipped slightly)
- (not necessary but maybe an upper mid band, either like Helios or Neve. I like how Helios adjusts the Q relationship with frequency).
I'd probably find that more useful for EQ'ing electric guitars in 90% of situations, it would save having 10 identical bands that all need assigning, and would make scrolling through menu's a bit nicer. Just checking the Helix Simple EQ, I wish the mid band could go above 4k, and an asymmetrical Q would probably be more useful (so cuts are narrower, boosts are wider). The high shelf is also REALLY low IMO (seems to be centered around 10k).
Not to say a studio style parametric EQ wouldn't be useful, I love the idea of the Helix line not necessarily being used in a traditional way, I think they make great "problem solvers" in various areas and it would be a worthy addition. I can absolutely see the likes of Sadites piling on a shitload of unneccesary EQ and compression (totally out of any context) and lots of beginners assuming "thats just what you do".