I was unable do do a search this morning. My internet is VERY slow and it froze up.
There is a great set of pics by Bobamaker about his neckseal details. It is pretty simple as far as sewing techniques go. If I can get a link later, I will post it.
You can get tackle twill at Websters
Twillusa.com has tackle twill also, but the color is not as good as Websters.
Here is a link to Websters...
http://www.websterfabric.com/products/polyPro.html
You need the uncoated poly twill. You would probably want to contact them for color samples. I don't remember what the best color is. The minimum purchase is 5 yards. You could make several neckseals with that much fabric, so you might want to make a run. I am sure plenty of people would want one. I have some cream color tackle twill from Twillusa.com. If you may want to buy just a small amount for a neckseal, please pm me. I could send a color sample of what I have. There is alot of debate about color and IMHO it is best if you get a good look at the color to make sure it is what "you" want. It is a very debated question. The search takes along time, but if you want the absolute best info, try it. By searching you will get many opinions, some correct, some not so correct, but you can make the best decision for yourself. There is much about this that is objective. If you have sewing experience, making this will be simple. PM me or email me I can help at all....
debbi@ladysewforus.com
Now I remember, here are the color choices and greyish is the color that has been most desired...
http://www.websterfabric.com/colorChart.html
cheers