Listening to Go Drummer right now. Rockin' baby!!!!
I wish I could sing like you, man!!!!!!! That would be way cool.
regarding mastering--just be careful with the mastering advice from that earlier post. I would suggest being very careful about compressing this stuff too much, especially if you're trying to keep a '70's' sound throughout the process. I don't think they squashed stuff to hell in the 70's like they do now. My (very humble and non-expert) advice is to do as little processing as possible at the mastering stage, only enough to help it along a little. But if it improves the overall sound, then do it!!!
Just my opinion. Whatever you do will be well loved my many of us here, I think.