After attempting to mount FAB version I to the Bendix RSA Fuel Servo, I realized I made a mistake regarding the shift direction to account for the mixture lever interference. There was no good way to fix this issue, though I tried. I've done this type of thing more than once... and learned it is best on the long run to order new parts and strike it up to another learning experience.
New parts arrived today, and I was careful to fully understand the shift needed so the mixture lever impact is minimized relative to how much trimming of the FAB is required.