Groom makes no reference to the total number of teeth per each reverse. Other than to say:
Reverse A: Beads smaller than rev B. Gap between beads.
Reverse A*: Beads larger than rev A. Almost no gap between beads.
I'm guessing that the reverse B mentioned here, is that used for 1925 onwards.
Interestingly, he says that for 1912, reverse A and A* exist also. Centre of 2 over bead, centre of 2 over gap, respectively. Didn't know that. Something else to look for......
1925 pairings as per Freeman. 1+A, 2+B. NOT intermixed. Or are they? Maybe Gary knows different? Now theres a challenge to find.