Re. the flex targets: recently on one of mine the interruptor broke off - I only noticed it because the pin started complaining about that switch.
It looked like this:

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As these special switches seem to be unobtainable - at least in transparent - I created and 3D printed a little fix for that. It goes over the remainder of the interruptor and gets glued onto the back of the switch door (or whatever you call that). I added a standup target pad to the back to cushion against hard hits and now I´m crossing my fingers that this will hold.

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I followed Cliffy´s advice and bent the backstop at a different angle and this worked really well for me. The danger of breaking the assembly isn´t big if you are careful. In my first approach I bent it too far (~60 degrees). This reduced the bounces to zero , but also the number of balls making it up to the turbo to 10%, because the balls are hitting the backstop on their way up . The Cliffy recommendation of 45 degrees seems about right. I was getting almost no bounces anymore.