My dad stopped by again and we tweaked settings for the vector monitor. It looked like it had be serviced by someone who didn't have much experience with these fairly unique monitors, and once they had confirmed it was 'working' as well as typical arcade monitor they walked away. We made some huge improvements and now the game really pops.
Time lapse photos of Tempest are interesting. Here are a few with my crappy snapshot camera. I'll post some better ones later when I can borrow a better camera.