I've never really lucked out with silnylon at the local walmart - have found some other cool fabrics though. To add to Tango's post, use polyester thread and I prefer webbing for the tie outs. I use a straight stitch, and many times will double stitch for strength. With the tie outs, it helps to add a small piece of extra fabric or webbing to strengthen them. Check out the make your own gear projects page here at TLB, and you'll find a lot of instruction. Lastly, if your stuff really is sil-nylon, its gonna be slippery and a pain to sew. I'd suggest sewing a few stuffsacks to practice with it before embarking on something bigger.