what to do with these two new speakers, celestion GT75

ok, I've been blessed with these two speakers which I won from hanging out with a bunch of Jesus loving guitar nuts....(yes I'm one of them too...)

now I need to know what to do with them.

I have two amps right now,
a 60 watt 212 hotrod deville, stats say 2 to 4 ohm load
and a 15 watt 112 Blues junior, 16 ohm load

these celestions are the gt 75's 8 ohm load?
I read that they are like beefed up vintage 30's???

can I swap out the jensens out of my 212 for these?
or should I build or buy an extention cab that I could use for either amp...

I did plug my blues junior into a 412 cab once, it was humbling how much better it sounded with the big cab

so....any ideas?

I'm not very good with the ohms department...so some advice would be appreaciated....
thanks

what kind of a sound difference could I expect to hear?

I mostly play classic rock & blues, and P&W.

Mine say G1275T on the back. I pulled two of these G12T75's out of my Marshall 1960A 4x12 cab and put them into my Tophat KingRoyale 2x12 open back combo. (I bought the amp used and the speakers that came in it were ok, but I thought there was room for improvement). I never liked the Marshall cab, it always had zero personality to my ears for some reason. But when I put these speakers in the open back Tophat I absolutely fell in love with the amp. This amp is similar to a Vox AC30 as I understand it, with EL84 tubes and I feel it has a lot of midrange content to its tone. I've heard the G12T75's have a bit of scooped midrange to their sound for the heavy-metal-axe-through-marshall-stack thing. In any case, in my situation with this amp they are an ideal fit. The tone of the amp tightened up and gained authority with a nice non-flabby bottom end and crisp highs and mids that cut right through the mix. It instantly seemed to gain headroom as I don't think these speakers break up as early as a vintage 30 for instance. Power chords etc. sounded soooo much better. It also has a great compression feel when you dig in that I'm sure is also a product of the tube rectifier but is much more noticeable with these speakers. So for me, they are outstanding in my open back 2x12 combo, but were lackluster in my 4x12 closed back cab. Go figure. This was my experience and someone else's with a different amp would probably be completely different, but I stumbled on a great combination and will now never part with this amp or these speakers in it. Your mileage will probably vary dramatically.