Since I had to work, I only had a few hours to work on the pinball today. I did some work on figuring out the circuit I need at each solenoid, it's close. Using a 555 in monostable mode to drive a TIP120 that drives the solenoid. I need this so that I can direct a low power signal to the score circuit at the same time (e.g. when you hit a pop bumper) and also for when I need to drive a solenoid for other reasons like the drop target reset.
Once this circuit is worked out, I need to make a whole bunch of them.