Hi Sea_Wolf +
I started playing pinball in the very late 1960ies - "Shangri La" was my first love, my number one pin is "Far Out". One thing I dislike on the late EMs is the feature "every new ball given starts with one bonus given" --- I want the bonus to make by myself, the feature is complicated, we may have problems when we want to test (for example) the Ball-Release-Coil.
Owners of late Williams EM-Pins (Space Mission etc.) should know this video, see https://pinside.com/pinball/forum/topic/em-pinball-circuits-basics-to-not-so-basic/page/3#post-3587920 - SteveFury made the video - I somewhere read in pinside that Steve went "R.V.". The whole topic is good - basics, Williams and Bally,a lot of Gottlieb specifics. Greetings Rolf