When I got both neck and brow trims I test fitted them, and as I figured, I had to modify them. This is what I did:
For the neck trim I VERY carefully used a razor blade and removed half of the trim as shown in the photos. I did this because even though the rubber was soft it seemed too thick to bend around some of the contours, especially near the vocoder. Once I did that I used some super glue gel to glue it in place. Probably didn't have to, but I wanted it to be super secure. As you can see I also cut a small piece to put below the vocoder. I think it looks good.
You will end up with this:
Since I grinded the brow up more there wasn't a nice even edge all the way around anymore. So, again, I VERY carefully cut part of the trim so I was left with an L shape. Now when I'm ready to put it on the helmet I'll just put some glue on the bottom edge and it will still look as if it's going under the lid(see photo).
Here are some photos with the neck trim, Stomper's aerators, and new eye lenses installed. The brow trim is only in place with some tape. I'm waiting to get the ears before I permanently install it in place and apply the tube stripes decals.