You said "I have had such a costly disaster with upgrades that I live in fear of doing them"
There are three ways to back up your system (personal and data files are different)
mylivecd you are using. If you like that stick to it.
There is also a clonezilla live cd/usb, and the O-P way which is in another thread.
I find clonezilla easy and it has saved me several times. Easy to make an image, slightly more difficult to recover. I back up my system partition /dev/sda1 on a regular basis so when needed I can easily recover.
Have a read of this:http://www.pclinuxos.com/forum/index.php/topic,83521.0.html