Catapult mechanism motors

My team is trying to fine tune a T-Fling and we are wondering whether most teams use 1 or 2 motors for it? When we try 2 motors it seems like they are not quite in sync. We are still trying to get it to shoot more forward also. Low goal works but high goal still needs tuning. Any tips would be appreciated as this is a more advanced build for this team.

Why not use a long shaft to sync two 60-T gears?
And I want to know whether this catapult can shoot one ball or not.