The only thing necessary to make a 3 wire setup work with either a 10-SI or a 12-SI alternator is an idiot light or a diode in the circuit to prevent run-on from feedback to the ignition system on shutdown. See the photo above- - - - -the white wire in the pic is the one that needs a diode. I use a small 2-wire peanut bulb socket with a red lens (not a LED) on my tractor to provide the excitation to kick off the charge.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!