No need to use a power rectifier like you've shown, the sensing circuit carries no appreciable current. In my last vehicle, I just used a couple of 3 amp diodes in series to get about a 1.4 V boost, with a switch to bypass as you've done.
With the Ford IAR and 3G regulator the yellow wire serves as both the 100% power supply and the voltage sense lead to the regulator.
Alternators with regulators featuring separate power and voltage sense lead wires are extremely uncommon.
Perhaps you are thinking of voltage regulators that utilize a half phase rectifier off the diode trio, and have a dedicated voltage sense input. Such as the Delco 10, 12, 15, 17 and 27 SI series. With this alternator the regulator plug marked # 2 is a dedicated voltage sense lead, and can be biased not only via rectifier but by resistor. The Delco 27 SI series 200 (truck) alternator even had a square black cap atop a block for the regulator terminals. By rotating the block, various resistances were had changing the regulator set point.
It would take a huge resistor precisely quantified to power the Ford regulator. Which is impractical. The power rectifier is the easiest and most cost effective. If more resolution is need in the voltage setting, a Schottky rectifier can be used alone or in series with a silicon rectifier. A silicon + schottky would amount to a 1.4 to 1.5 volt increase.
