Okay, here's an update. Thank you Shelbie! I printed the PDF and followed it to the point of drawing the lines. I then did as PatriceJ mentioned. I drew a couple of partial lines (just an inch or so) on either end of the tube and that was so that I could line the two sides up more precisely. I sewed the seam to make the tube and then used my rotary cutter and a smaller cutting board on my ironing board to cut the spiral. 1 1/2 hours later, the binding is pressed and ready to attach to my quilt!
I think the problems I experienced the first time came from over-handling the fabric--and not knowing my straight of grain from my bias (duh!)
Thanks everyone for you comments. I don't know if this is a technique I will use often, but at least I know I can do it if I have to!