Adrian, MI
I have a TZ that I could never get the playfield perfectly leveled top to bottom. It either had a slight warp to the playfield, or the mounting of the pivot points in the cab or the mounting of the lockbar were slightly off. I found that if I put a 2 to 3 mm thick shim under the right playfield hanger bracket (on top of the lockbar where the playfield hanger bracket sits on it), it leveled the playfield perfectly. I put thin double sided adhesive tape under the shim to hold it in place when I lift the playfield to service the machine.
So to sum up, I basically had to stick an 1/8" shim under one of the front hooks as you noted.
