I used superglue gel. I attached one half of the brow at a time. I placed a line of superglue half way around the helmet, lined up the rear edge of the trim with the left side gray trapezoid, then placed the trim down.
After a couple of minutes, I placed another line of superglue down, then placed the trim down and lined it up with the rear edge of the right gray trapezoid. The trim can stretch a bit so you will be able to pull it around, if you need to, and line it up with the rear of the second trapezoid perfectly. Test fit before you glue! The results were clean, fast, and perfect.
Vince