So Pin-Golf is: a target score is set per machine. If the target score is reached on the first ball. it's a "hole in one" and marked on the score card. 2'nd ball marked a 2; 3'rd ball a 3, if the target score hadn't been reached marked a "4" for a 3 ball game (or a "6" for a 5 ball game)
Extra balls can be played and considered the same stroke.
When you reach the target you stop playing til your teammate reaches the score & move on to the next "hole"
Many times every one tries on their own to get the lowest golf score for the course. (ideally 9 or 18 machines or "holes".) in cooperative play both players add their final scores together and compare against the other teams.
There are official "Pin-master" scoring where it's possible to have up to 10 strokes on a hole then finishing in a bracket style competition where you're still playing pin-golf https://www.ifpapinball.com/tournament_pages/pinmasters/rules/
Quoted from schudel5:
Split flipper (Zen) tournament. Pair a player with a non-player as a team. One player operates the left flipper and the other the right. Maybe have them swap sides for each ball or on different games or just let them decide what they want to do. Lots of fun and the experienced player will have to tell the inexperienced player what to shoot for.
This is great too! another way to do this is on a 4 player machine, coin-up 3 players: player 1 plays alone, player 2 plays alone, and the 3'rd player coined up is split flipper.
I don't know exactly where they come up with the target scores. it's usually less than what a recommended replay score is on the replay card by more than half.