Since I'm new to the game of using practically antique gear (I know...stop yelling....some of you are older than me!), and I'm not an electronics engineer, I needed to educate myself on some of the terms that get thrown around so loosely in forums. I understood the rough idea of bias and offset (as it pertains to amps), but lacked background. I found this article which does an excellent job of explaining why bias is important, why high wattage AB amps have some advantages over smaller ones, and what issues are common with VR pots used for bias adjustment. Good stuff.
http://www.tnt-audio.com/clinica/bias_e.html
You have started from scratch and seem to be progressing well. An excellent forum for learning is http://www.diyaudio.com/forums/index.php
Good wishes.