don't forget the right and left bottom rollover switches. Those are the ones I'd wedge closed and cause the 1000 point relay to stick on.

wrt the initial questions:

1] I don't, but if ya look at manual page 20, all you need to do is make sure the wiper finger running around the outer segmented ring of copper traces is sitting on the same segment on both contact plates. i.e. more-or-less line up the fingers, but it doesn't need to be perfect.

2] the match unit wiper position won't affect anything. If they are misaligned, all that happens is the lit match number on the backglass would be different than the number you get a credit for.

the reason there's lotsa wires and two contacts plates is one plate is in the 6V lamp circuits and the other plate is in the 24V game circuits. One wire for each digit 0-9 and a wire for the circuit feed is needed in each circuit, so each contact plate has 11 wires on it.

there's a switch in the middle of your match unit that turns on/off the change relay. That relay is controlling the rollover lights. If your match unit isn't stepping, your change relay wouldn't flip-flop.

might as well check the switches/wires on the change relay also. If you have short there, doom and despair.

you mainly care about the blades/wires on the switch B and C on the change relay.

the big plug going to the cabinet likely has the power wire for all the coils in the head on it, so yanking that one will disabled them all.

the playfield plug is more interesting and narrows it down to left or right bottom rollover switches or the
swinging target step-up unit EOS (end of stroke) switch.

got good pictures of those three things? If you aren't sure what the EOS switch is, take pic of entire unit and look for switch that is activates when the step-up solenoid plunger pulls into the coil.

do you have a voltmeter or jumper wire?

those look like the EOS switches. I assume the stack lifted when the step-up plunger pulls in? If you don't see any shorts at the wiring, time to punt that idea.

after checking daveh's suggestion, I'd yank the playfield plug then one at a time use a jumper to connect each pin to its respective socket hole. No 120V on that plug, so it's pretty safe to poke around.

if/when the 1000 pt relay powers, you know which wire is doing it and with some luck you can tell which color it is. I guess you don't need luck since the plug chart is in the manual

oh ... the set up relay. Are you having the problem when the playfield is tipped up? Since the spinner is gravity-based, with the playfield up the spinner switch is sometimes stuck closed. If your spinner = 1000 when lit is on, you'll get the 1000 point relay sticking on also.

I forget about the spinner about ... pretty much every time.

daveh is talking about the plug pin on the advance bonus adjust plug, not a peg on the bonus unit itself.

in the schem below, he's looking to disconnect the yellow highlighted circuit.

the blue highlighted circuit is the spinner which could bite you if the setup relay is powered or the switch is stuck closed and the spinner switch is closed.

the red path goes to the 1000 point relay.

space mission schem (resized).jpg