I usually just lightly slap them. I highly encourage to fund a player who can do the sidespin balls repeatedly a beer and ask him to feed you balls. I encourage you to try different things. In my opinion slapping it firmly is good option. Doing a counter side spin top spin is also good option...
Welp. I get you. But the same machine. Physically the same robot, that stuttered a lot of poo orange balls by Joola, moderately stuttered with Huieson do not stutter as much and keep tempo with Tibhar ***.
I had similar issues. The thing is.. I gave the robot to my coach for testing. He did shove a bunch of 3 star balls tibhar competition, and it is working really good apparently...