There was no reason to run separate voltage amps, since there could not be separate feedback loop signals (since the secondaries were paralleled, there's only one feedback signal source).
Perfectly sensible. I was just curious how close to Bogen's method you got. Single voltage amp seems like it would help make sure the drive to the two inverters is the same too, no chance of tube variables becoming one more thing to worry about.
Looks great too.