Amp extension cab question

[Karma1]

I've been hearing a lot from people who own the Fender Super Champ XD saying how great it sounds through an extension cab. I have one of those amps and have been thinking about adding a cab. I saw a good deal on a used Mesa 1 x 12", but I'm wondering if going from the 10" speaker in the Super Champ to a 1 x 12" cab will make that much of a difference. Should I be looking at something larger like a 2 x 12"? One factor is that I don't want to get something that weighs a ton, so I'd like to keep it on the lighter side for portability.

 

I also saw a 2 x 12" Marshall cab which was 4 ohms in mono and 8 ohms in stereo. My amp is 8 ohm, so is that cab useable with my amp?

Any advice on these questions would be appreciated.