Thanks guys,
It seems to be a pretty minor point as to which I use. It will be stretched over a wire mesh frame so there are lots of opportunities to sew it on without a lot of stress. I might as well try the poly as I have never used it before. An educational experience. It will get coated, so the loose weave is not that much of an issue once it gets coated. The Wee Lassie that will be built this winter as well will still be what I know best, nylon.
I tried to post this on qajaqusa and it has not made it there, apparently too off topic. Nice to see them try to get rid of the spam.
Scott