I would go with neck seal, It may be uncomfortable. But for me, I like a good balance between realism and being comfortable. I will be attempting to make my own under armor for my ODST armor. My CS SF Dress Uniform was made by me, with the help of a seamstress friend who owns her own company and I picked up a lot of tips. Here is my flat out advise, if you plan on wanting to make your own neck seal that will be comfortable plus authentic. Then go with something that is cloth and will be a temp under armor for your costume, that way there is no rush on the neck seal and you can take your time to make it the way you want. Hope I helped a little.