It's going to be different for each guitar. I find one in particular -- I think it's like 4 or 5 down from the top left... something-or-other Fast1 -- works particularly well for REALLY heavily-distorted guitars. None of them are particularly subtle, you won't have a hard time finding what sounds better for your mix than the others.
Here's a link to a project I'm working on. This is my from my grindcore band's full-length, no vocals recorded yet. Not the final mix but I'd like to think it's close.