I’ve gotten 22-24 pound birds in my 22.
Two 12’s would be fine too. Shorter cook time as well.
Not quite as impressive but, that way, the second bird can come off when folks are ready for seconds and it will be warmer.
Just a suggestion.
My method has always been “Un stuffed, 11 minutes per pound”
Never a failure...yet!
It will be delightful, enjoy.
Carving tips in the “Krispy skin” thread, if you are interested.