Hello, I am going to try making my own tarp (with zippered doors). I have a question about the ridgeline. If you make a flat felled seam, does that mean the side you sew the seam down to becomes shorter than the other side? Is this something you normally add allowance for? I would like to put doors on my tarp and since the doors would have to zip together, I would like the tarp sides to be of the same dimensions so the doors would fit nicely together. Also, whats a good source of zippers and what kind of zippers should I look for? I think reliability would be important to me, followed by the weight of the zipper. Thanks sorry if this has been asked somewhere before.
