From Wilwood instructions:
Adjust parking brake:
1. With parking brake off, loosen adjustment bolt jam nut (on the parking brake caliper).
2. Tighten the adjustment bolt until there is some drag on the rotor.
3. Repeat steps 1 and 2 for the other rear wheel caliper.
4. Back off adjustment bolt one-half turn on each caliper.
5. Ensure there is no rotation of adjustment bolt and tighten jamb nut 80-120 in- lb. on each caliper.
6. Check for drag on each rotor. A slight rubbing sound during rotation is acceptable.
Since you have drag already you may need to back off the adjustment bolt to get clearance and then follow the above instructions.