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

The old and new style alternators are very similar, it takes 2 wires for a field. The old style had one grounded at case, so when you ground the point where blue wire connected, same electrically. There are carbon brushes that feed the rotating field. There are actually insulators that are used for the new style alternators. It easily changes style.

The new style alternator, with new regulator feeds one terminal like you had wired shown above, then the green wire is switched to ground for regulator action. But as I said earlier, old style powers green wire, so no current flows and no worky when blue powers other terminal.

Just don't add ground to blue if it also connects to Ign, wires will smoke, car no start.