I have them on 3 different speaker cabs and I'd put them on any other multi speaker cab I own in the future. Very handy if you run amps with different ohms or as a stereo rig.
Just pay attention to the wiring. Hopefully they have instructions. If not tubesandmore.com has instructions on their website.
I don't like stereo in the same 2x12 as there is just no separation and the effect is lost (unless you stick a mic on each speaker).
May be off-topic, but what I do on my 2x12 loaded with 2 different speakers is wire them out to separate jacks @8 ohms ea. My amps have 2 8-ohm out jacks, so I can run either speaker for different tone, or both if I want to mix them. Most of the time even 1 speaker is plenty loud and sounds better in the big box than in a smaller 1x12 box.