My wife and I came up with a good formula for our games, but I'm not remembering it at the moment (gin will do that). I think it was 10%, or maybe 20%, of the #1 score on Pinside was the hole in one. You want to be able to get a a few of those per match. I know I asked on the Pinball Enthusiasts Facebook group once, and most people were like, "what the fuck's Pin Golf?" Weird.