Offcenter doesn't matter as long as she's sitting parallel to the rotor centerline and not touching anything that she's not supposed to.
I don't know anything about Willwood M/Cs which are usually backwards-plumbed compared to any and all Mopars A-bodies I have ever worked on.
I like my brake-pedal directly connected to the primary piston, operated mechanically. In a Mopar mc, the secondary piston is operated hydraulically ...... until a brake failure occurs; then the back-up mechanical system comes on line.