well to get this done electronically is just an itch of hobby u can say. Otherwise i don't care as long my air con runs fine. Btw, if anyone is interested this gen set is a ST type head directly coupled to 800cc natural gas automotive engine. Gas varies in pressure and impurities from main supply lines and that affects governor performance otherwise its quite capable.
With electronics, it would be quite simple..pull the throttle until desired Hz is reached. I don't think electronics involved here are complex. In simplest terms, a sensor detects Hz, an IC programed to display it on LCD segment and forward signal to servo controller. Kind of extension to home made AC Hz meter