After the first verse, then two guitars break out (like, guitar 1 on R channel, guitar 2 on L channel like most artists do)
But before that verse, I have my guitar drowning out my lyrics in the center!
First, you have to ask yourself exactly what you want. Better yet, experiment. You’re undoubtedly going to end up experimenting anyway.
Do you want the guitar panned to the center for the verse and then have it jump to either side (Guitar A) after the verse and add a new guitar on the opposite side (Guitar B)? That’s not uncommon, but it’s never something I would personally do. I find tricks like that disorienting (though sometimes that’s the desired effect).
In order to do that, you’ll have to split Guitar A into two different tracks because Audacity doesn’t allow you to dynamically change the pan setting on a single mono track. It might be difficult to find a good place to split the track too, and the track will “jump” instead of shift over to one side.
A better solution might be to split the guitar into multiple takes with 3 guitar parts. Have Guitar A only play during the verse and pan it wherever you want. Then Guitars B and C come in at the same time that Guitar A drops out at the end of the verse. That way you’ll be able to mix all three parts separately and you’ll avoid any jarring pan changes.
At this point, I’m going to explain a bit about my personal opinions on how to pan things. By all means feel free to ignore me, there are no rules to mixing tunes. That said, I think it’s quite rare to hear instruments panned hard left and hard right as you seem to be describing (except on older recordings due, in part, to the limits of older mixing consoles). Most of the time I don’t go past about 60% left or right with an instrument like a guitar. I also don’t like to limit myself to ‘balancing’ the stereo spectrum. I wouldn’t be afraid of panning a guitar 20% right and then having another guitar panned 60% left. Ideally the “more important” or “more constant” instruments would appear closer to center than the other instruments (this is why bass guitars usually end up at the center or very close).
In the case above, I would feel no qualms about using two guitar tracks and not balancing them. Guitar A would always be present and might be panned 20% left all the time. Then guitar B might come in about 50% right when it’s needed. I would pay careful attention to the loudness balance though and use the envelope tool to adjust Guitar A and the vocals so they mix the way I want them to.
Is there a way I can make the guitar seem panned off to far left and right, but without losing it’s amplitude?
Apart from actually boosting the instrument panned off to the side, not really. You lose 6dB moving from the center to either extreme edge. So you can boost the track by 6dB to make up for that and it will probably sound ok on speakers, but if you listen on headphones that track will jump out more than the others. The easiest way around that is to avoid pushing tracks all the way to either edge as I’ve described above, but sometimes pushing something to the edge is what you want. In that case, I say learn to live with the volume drop. It’s better than ruining the mix for a headphone listener.
Is there some kind of plug-in that can possibly roughen/mangle a channel so that they contrast eachother?
Yes, just about any effect, but most often EQ. If you’re talking about guitars, then change the amp settings a bit between takes, or use a different pickup setting instead of EQing it. But if you’re asking about making the vocals and guitar more distinct then EQ is probably the way to go. Without knowing what kind of tone you have now and what kind of tone you want in the finished product, I can’t say any more than that.