Pac-Man and Ms. Pac-Man are the same board. If you look at your Ms. Pac-Man board, you will see Pac-Man screened on the board (if you don't see it, it may be possible you have a bootleg, which is not covered here: confirm at the link below). Pac-Man is another game which has had years of research done on it. Check Google for your problem. Likely it's been covered there, or in the link below.
Cocktail mode: It is not entirely clear from the Pac-Man/Ms. Pac-Man schematics how to put the game into cocktail mode. If you connect pin R to ground, the game will now operate in cocktail mode.