I'm a big Swervedriver fan! So I know where you're coming from. First, yeah, clean guitars and distorted ones should be on different tracks. Swervedriver used alot of effects--alot of delay, alot of reverb. They had a really dense sound, one of the densest and loudest that I can remember on record. I'm not sure how many guitar tracks that they used, though. Lots of texture to it, too--i'm guessing that they used lots of tracks to mix and match to get that really dense sound.