I posted the instructions several years ago, but SEARCH won't pull it up. I can re-post it.
NOTE--Comments below revised 7/11/06
Per the FSM, the "notched wheel" (Adjuster Nut) inside the park brake unit is used to achieve the proper OD of the brake show. The Adjuster Screw threads into the body of the Adjuster Nut, and what you are actually doing is adjusting the threaded portion to create a spec clearance between the shoe and inside of the brake rotor.
Rough adjustment of the park brake shoe can be done by moving the shoe out of position to clear the Adjuster Screw so it can be rotated. If the adjustment is already close, just rotate the screw 180 degrees and re-check the adjustment.
There is a special tool (a gage) that is used to set the dimension, but in the field, no one is likely to have that tool. PBR does have some specific recommended limits to how far you can take the adjustment. The nominal dimension of a properly adjusted shoe against a NEW rotor is 190mm, or ~7.48", and the max adjustment is about 5mm, with a minimum shoe lining thickness of 1.5mm--after that, replace the shoe.