Is it possible to keep old style electronic VR with a dual field alternator?

The basic operation of a regulator is an electrical comparator. The mechanical regulators worked the same way. The mechanical regulators were a normally closed relay, that opened field current when relay coil voltage was high enough to open contacts. The resistors, return spring set the threshold and hysteresis. Hysteresis is the dead zone of a few tenths, in the comparator action. A HVAC thermostat works in a similar fashion.

Electronic regulators work the same way, but transistors are a much cleaner switch than contacts. They are not influenced by vibration, erosion, temperature variation, insects ... a huge list of others.

With the switching, inductance of field coil stores the current, so the current builds in a ramp fashion, and also has a smooth decay. With a high resolution scope the current observation is similar to a fine hacksaw blade.

Transistors are efficient as switches, ON, or OFF, but not good, very lossy like resistor in active state, wasting electricity in excess. Today's electronics power controls are switch based, and methods improved over basic comparator, for noise reduction, power factor improvement....

The field winding generates the North and South in the interlaced end pedals. As they spin N-S-N-S, or S-N-S-N it does not matter, rotation direction, nor field polarity.