Yes, this is probably the most flexible setup. For my bridgeport, I
have an 8" Horizontal/vertical Phase II rotary table with a tailstock
and a set of dividing plates, and a homemade adapter to mount a 4-jaw
chuck on top. I also found a surplus 4" universal dividing head with
a 3-jaw chuck attached (beautiful thing) later on but I wouldn't have
bought one as a first choice new.

What you need to do is run the rotary table in vertical mode with the
tailstock, with the gear on an arbor in between centers. Depending on
the tool, you'll be running either a commercial multi-tooth form tool
in a slitting saw arbor, or a single point tool in a flycutter/boring
bar holder (which you'll probably have to make yourself). Set the
cutter on centerline vertically, set your depth of cut with your y-
axis dial, and use your x (longitudinal) feed to cut each tooth.
You'll probably need to take more than one pass, going all the way
around the gear each time.