Dan - the netting stretch tends to accumulate when sewing longer seams. Check your netting's weave to see if one direction stretches less than the other. Cut the netting piece so that this direction is parallel to the direction of the long seam. Some stretch may still accumulate, such that you reach the end of the seam and there is leftover netting. If you can leave the "foot end seam" - perpendicular to the long seams - for last, then you can simply trim the excess netting before sewing the final seam.
I find the above approach normally eliminates the need for pins. A simple felled seam is a good idea with netting - the first stitch with a 1/2" allowance, and the second stitch to sew the allowance flat to the body of the project. The sil-nylon edges may fray a bit, but usually it's not a big deal. Otherwise, there's the flat-felled seam, which is a little more tedious, as you may know.