I have built a Hole-in-One machine. I acquired the plans from Ron Mitchell at Skegex in 2019. The balls are not ping pong balls but are balls removed from roll on deodorants.
My next model is from Model Plan no. 172 Endless Ball Chute designed by Peter Matthews. This model does use ping pong balls.
These photos are from the Chickerell Steam show near Weymouth 2019.
These videos are from the M Shed SWMC Exhibition, Bristol, in May 2019.