Got my board in and installed it. It is a very neat piece of kit, when it works. So far it is proving to be unreliable.
The optos were not soldered very well. I kept intermittently losing track of balls. Visual inspection showed some pads had 0 solder on the front side leading to traces.
Currently I discovered that while a plastic backing kit is included, it relies on using two of the original metal screws for the microswitches. What I found is that after having installed/removed the board several times one of the screws scraped part of the masking away. There is a ground plane or a trace underneath too close to the screw head and now my board works perfectly fine, until that screw is installed and then it likes to emit a loud buzzing. Some of the optos will show both red and green when a ball is not over them and the game does not see any of the balls.
Trying to decide on what fix to go with. Electrical tape is easiest, but it looks like a hack on a board I just spent good money on.