For our game the following helped a Lot. YMMV...
1 Level and pitch on this game are rather critical as it has many design elements that are effected by more/less pitch. (center loop bottom exit, skill shot lane, etc). Left to right must be perfect and I found around 6.8 to 7 exited the ball out of the skill shot with enough speed to not hang up and also Not hit the right sling on its way down.
2. The ball gate Does have some adjustment. Loosen the Left nut and right. The design pivot point is the left nut, the right one is in a "T" slot allowing you to move it up or down slightly to increase ball gate angle. I moved mine up just a touch and all is good.