Quoted from Audioenslaved:
Had a great game on houdini tonight. Finally got around it moving the C target to the left and whoa Nellie what a difference that makes I can now consistently hit that inner loop shot and not have it rattle around and dribble back down! Catapult is still not hitting though. I don’t think it’s made it in the last 50 throws although it is hitting the same spot now with the upgraded power supply... I’m trying to find the definitive instructions but the thread is so long and is super frustrating!
Physically rotate the catapult mech. Loosen the 4 mounting screws and twist it.
If that's not quite enough, elongate the holes in the mounting bracket to give you a little more adjustment.
See my posts on this, if fully documented at this point with pictures I think mostly...