I'm beginning to think that the problem I had with booting to the Kubuntu disc wasn't the disc. I just tried viewing the content of the disc in my file manager, and I had to recycle the tray several times for it to read it. I'm going to connect another optical drive and try it again. Not sure about the overall size of the files and folders on the disc, but when viewing the burned area on the disc itself, it only uses ~5/8". That doesn't look like 700MB+ to me.