I just posted in that one thread below this one.
Basically, I built a copy (sorry, its too cool!) of your Golf Ball Beast over the past three weeks. I have the frame done, but one major setback I am having is the throwing end. I have an arm, the counterweight arm, primary and secondary triggers, but i can never get the arm to stop its forward motion after it has flung. I'm hoping it will be as simple as adding a projectile, but I don't know. I guess I am just horrible at tuning.
My tuning method thus far has been to rotate between the holes I have drilled in the arm and the counterweight arm, trying to get that perfect combination, but to no avail. Any tips and or pointers?