Before doing the final firewall forward install, the propeller has to come off. I also have to squeeze one last rivet on each gap filler. Having tried a few tricks, I had no luck with my pneumatic squeezer, maybe a manual squeezer would have worked. So I installed a Cherrymax rivet.

After some sanding, I spray a light coat of primer. There are some small imperfections that will be looked after before the final painting.

I removed the spinner and sanded everything. Some small problem areas had to be filled. When everything is cured, and after a light sanding, I should be able to apply a last layer of primer.
The picture shows the shoulder created inside the spinner.

I'm not happy with the results after the proseal has cured. So I removed everything and do a new small shoulder with epoxy and flox. It's harder than proseal, but will be easier to sand to make small adjustments.

The proseal trick did not work as expected. Before redoing it, I install the nutplates for the six screws that go from the spinner to the forward plate. It's the usual drilling, deburring, countersinking and riveting sequence.
I then apply a new layer of proseal hoping for better results.