The image is of an older NOS unit. The Woodward needs an adjustment box to set the parameters. Try to match the servo throw length to your newly made extension of the generator throttle arm. And like all governors the electronic unit needs your compromise parameters to establish a compromise between load change response time versus over sensitivity (hunting).
On an unfamiliar installation I have a prime mover kill switch at hand in case my genius outsmarted myself.
I'm a tig welder so I can make nice brackets just a little unsure of the wiring but thinking I'm going to try doing this mods . I see there a few different power control modules but is one a lot better then other ?
A servo is a control arm both directions electrical controlled by speed regulator box
The regulator senses 60 Hz to tell it what to do
12 volts for servo control. Need to match servo throw length to carburetor throttle arm. Longer arm is better to use all of servo throw length. This means faster + most precise speed control
Reaction time to load change is instantaneous but engine response lag time from instant "no load to full load" cannot be improved that is an engine issue not a governor issue
The servo must have an excellently anchored to engine mounting bracket
No mechanical even a hydraulic powered governor is as precise as a good electronic governor. Today, tomorrow, next year frequency will remain 60 Hz.
Again, this is not plug n play mounting wise. I recommend 1/8" steel for the servo mounting bracket with three to the engine bolts attachment.
IMHO it is worth the bother. I will research online for general instrutions.