Shirt Pocket Discussions - Backup DVD and Partition to DMG?

Yesterday I bought Snow Leopard from Apple on DVD. It arrived today.

(Yes, I paid for overnight shipping, because this is a weekend project and otherwise it would have arrived on Tuesday.)

Despite it being 8 years, 1 month, and 10 days after 10.6.8 was released, the DVD that they sent me was 10.6.3.

Fortunately I had anticipated this potentiality and downloaded the 10.6.8 combo updater before the DVD arrived, so I was able to update it fairly quickly, and then a quick trip to Software Update brought the rest of the available updates.

Now, I would like to do two things:

1. Backup the Snow Leopard DVD (despite it being 10.6.3) in case I ever want/need to use it again in the future.

2. Backup the Snow Leopard partition on my drive now that it has 10.6.8 and all of the other updates on it, so that I can restore to this "fresh" state if I find that I do something to my 10.6.8 installation that I want to undo.

I know I can backup the DVD with `dd` or something arcane like that, but I'd rather back it up to a DMG or something more Mac-like, and I assume SuperDuper can do this, but I'm not sure the best way to do this.

I tried to do #2 and SuperDuper seemed to want to do a "sparse image bundle" instead of a DMG. But I'm not sure if I can restore a sparse image bundle to a partition and make it bootable or not. I tried googling but all I found were a bunch of forum posts mostly, none of which seems authoritative.

Any help / guidance would be appreciated.

p.s. - not sure if it matters, but I am backing up the DVD and the Snow Leopard partition from my iMac which is running El Capitan (it's a 2007 iMac so El Cap is the latest it can run). Both Snow Leopard and El Cap are installed on the same internal SSD inside the iMac. There is a large (4TB) USB drive attached, which is where I plan to store whatever I create with SuperDuper. Thanks!