What sort of compression would you recommend as a starting point for Distorted Elec Gtrs, Clean Elec and Acoustic Guitars (threshold, ratio, atack, rel)

Also I have T-Racks and also Wavelab (Waves plugins, Ozone etc). What would you guys recommend for mastering?

And finally. Just trying to get my head around mastering so I'm not too familiar with a lot of the concepts and terminology. I've heard people talking about "2-bus" a lot. What does this refer to and what's it all about.

I know these are very basic q's for you guys but any info is appreciated.