Elongate the Front Plate Holes
Jacksel,
I just went through this same experience with my RV-9a and Hartzell C/S prop a couple of months ago.
My prop was resealed by a reputable prop shop. When they reassembled the front hub to the specified torque, the front spinner plate holes no longer matched the spinner's holes. They were off by 1/4" - 3/8".
As a side note, the prop shop told me that those 4 threaded prop hub holes were originally intended for assembly/disassembly. Vans conveniently uses them for the front spinner plate.
The solution was to create a template with curved, slightly elongated holes where the 4 bolts mount through the front plate. Remember, if you are off by 1/4" on the perimeter of the front plate, it won't take much near the mounting holes to achieve this.
I actually drew up my template in AutoCAD to make an accurate template of the elongated holes. I then taped the template to the front plate. Then, I took a Dremel tool and appropriate bits to slowly and carefully elongate each of the 4 holes, according to my template. I finished the the holes by lightly filing them smooth with round files.
If you would like any help developing an accurate pattern with CAD, just PM me. I would be glad to help.
Dale