Geesh !
I already had a 2480 , and a nice 12AY7.
I wanted to use a Pel-CEK12 since I already building a G7 with a DALE-M7 and a cinemag BV8
Don't assume. Everyone has different goals. I wanted something to compliment the U47-G7 type such as a C24/C12 type. Since the circuit was derived from this it seemed like a good idea.
Sorry, did not intend to offend. Once again, it will work, but you asked if it will work well... I think it is OK, and since you already have 2480, of course, go for it.
I however, have my own reservations about combining parts you mentioned.
2480 has a very small core and gets away with early saturation because it is a DU core (no "I"). To get some primary inductance it has lots of turns of pretty thin wire, so it has high DCR (which of course, loads the signal), and still does not have enough pri L. To me it sounds pretty boring, uninteresting, with poor bass, compare to the bigger core brothers. To get a somewhat better bass response you should use it with a lower mu and Rp tubes, which will also help to keep the transformer out of saturation.
Gus has already suggested 12AT7 and as you see there is a good reason for that.
Also, if it is your intention to get C12/24 type of sound I don't quite see a good reason of using CEK12. Yes, it is an edge terminated capsule, but it is about where the similarity ends. It's been many times noticed that the CEK12 backplate construction and hole pattern is exactly like K67/87 type, so don't hold your breath to expect it sound anywhere close to a five chamber CK12.
Hope it helps.
Best, M