I have a question, since I am running out of HD space on my SSD, can I (after I back up to an external drive of course) sign up to iTunes match, upload music, and get rid of the copies on my HD to free up space? I would have the cloud / iTunes match to access and will have copies on an external HD if there are problems. Would that be a bad idea? Or do I need to have them on my HD after I upload my music with iTunes match?
Yes, that would work. Just make sure that you look after the backup, just in case.