I sprayed the helmet with the Upol Gloss Clear coat and let it dry for about 48 hours. I then used Meguiar's polish to buff the white areas with a sponge and then wiped off any remaining polish.
While I was working on the helmet, I got after the gap gmrhodes13 pointed out on the pre-approval feedback forum.
I ordered a replacement rectangular plate from 850 Armor Works. It only comes in black so I timed the work so I could paint the helmet and plate at the same time.
I needed to take about an inch off the width. I started by cutting it in half and then trimming each half to the right size. I glued a strip along the back of one side and then glued the top pieces together. I then sanded and primed the plate.
Once it was primed, I painted it with the Monaco White and then gave it the gloss coat as I painted the helmet. I'm hoping the size reduction will show less of a gap when the new plate is worn.