240D and 300D mercedes had slow plugs 240 had mechanical "pull to glow" control. the 300 went to electronic timer relay glow still 30 sec .
the improvment of the glow plug to be able to almost instantly heat and glow red is where the modern engine is . point is if the glow plugs in the engine are the older style, all the fancy quick relays and controlers wont do a thing as the plugs them selves need mega amps and time to heat thus the need to hold the heat switch for 30 sec or more.
if you pull a glow plug out and find its bosch and can determine the thread size,diameter and legnth of heating element then a conversion to quick heat plugs is possible and thus a more "automatic" controler can be adopted to work with a transfer switch device. IMO
most all small single,dual,and triple low hp diesel's are all based on the kabuta block design.
the heads and fuel systems and electronics are the biggest difference between manufactures.
at least if the power goes out you can now fire up and still enjoy quality of life albit it might take 30 seconds to a minute to do so!!!