Here's a little writeup of the method I devised for accurately fitting the spinner to the prop, with which I was able to achieve a degree of runout so small that I can barely measure it. Basically I built a simple Lazy Susan / rotisserie jig which made it much easier to use a dial indicator for really accurate alignment of the spinner bulkheads and the spinner itself. I also include some tips for fitting the Cummins aluminum spinner, which may be helpful to someone (my method uses lasers, which obviously makes it more awesome).
Full description and more pictures here: http://www.rv7blog.com/2021/03/19/spinner/
Full description and more pictures here: http://www.rv7blog.com/2021/03/19/spinner/