The zippy 20g is great. No click, no feel of the click either. I use them for the buttons in my 6-button cabinet for fighting games. They have such a light touch and they pretty much feel like actual leaf switches.
The 4 in 1 "hack" is an improvement and absolutely wouldn't reduce the value IMO. Stock Ms. Pac pcbs are so common and readily available and nothing special.
Here's a little more info on monitor impedance depending on what version of Primal Rage circuit board you might end up purchasing:
https://forums.arcade-museum.com/showthread.php?t=312436