"I think spinnaker is junk and would never waste my time or money building anything out of it. Its noisy, tears easy and is barely water resistant."
That's interesting. Maybe you got a hold of a bad lot of it.
I'm happy with the spinnaker fabric that I have. My GG SpinShelter is my favorite, and I purchased more spinnaker fabric to sew my own waterproof stuff out of it.
"Its noisy" If you don't have it taut, it can rattle. Solution, stretch it out better.
"tears easily" Maybe with yours. None of my spinnaker has any tears at all. If you didn't have it taut, then it can rattle so badly that it weakens and tears, I guess.
"barely water resistant" Maybe with yours. Mine seems to be nearly perfectly waterproof. It is so slick that rainwater drops just shoot right off.
Look around. Maybe there are better types of spinnaker fabric. There is a slight difference in appearance from one to another. At a distance, they all look alike.