ITunes :: Library To External Hard Drive?

So, my iTunes library is getting too large for my computer's storage capacity. I'm thinking of moving some of my library to an external, USB hard drive. However, I've never done iTunes through an external hard drive before and I have some questions. Can I copy new discs (import) straight onto the external hard drive? Or do they need to go onto my computer first then get transferred to the hard drive?Can I still use iTunes Match and pull songs from the library on my hard drive and from the main computer?To partition a library between a computer and an external hard drive, do I need to activate sharing or anything special? Or will the computer/main iTunes library just consider the external drive to be a different location for some of the tracks?How would I backup the external hard drive? Would Time Machine (running off a separate hard drive) back up another external hard drive if they were both plugged in?Can you burn the entire library to data discs anymore? Or do you need to make a playlist of your entire library? If the latter, is there a way to turn off the message about iTunes in the Cloud playlists only accepting songs matched or uploaded? I have some songs that erroneously did not get matched or uploaded. If I try to put them in a playlist and burn it to a data disc for backup, iTunes won't do it.