Part 1. Use the weakest ball you have. Plastic included. You're going to know if you missed then.
Part 2. As far as playing different parts of the lane, it's all about perception. What I do, is draw a line from my shoulder thru the arrows area of the lane to the breakpoint I want, and then try to let my arm follow it. Now, if you want to move in, usually a hand position change is all that's needed. If you're trying to go left to right, and you're usually a down and in player, try turning your wrist towards yourself slightly, and see the effect it has on ball roll. When I have to really open up a lane, I will do that just to create some more tilt.