Yes, in general, if you are going for a hard rock sound, lower your gain. I'd set it right at the cusp of being 'too low' for you, and then dial it back a hair more. When you double the part, it's going to sound like there's more gain (because there will be).
My last record, I tracked one side with a Vox AC30 and a Bogner 101b, and then doubled that with a SLO and Marshall Superlead. Each cab had 2 mics on it so there was a LOT of choices when it came to creating the tones.