Before starting a project on expensive material, learn to sew lightweight fabric. Silnylon is slippery, UL uncoated nylon is also slippery and snag prone. There is a learning curve to machine stitching, not rocket science, but mechanical and tricky. It takes practice, and practice is better done on small projects that use little fabric.
You could go to the nearest fabric store and buy the cheapest, lightest, sleeziest fabric you can find to practice on. Look in the remnant bin for cheap cloth; every fabric store has one. If you can't find anything suitably light, get silnylon to make stuff sacks in a variety of sizes. It's great practice and you can always use them. owfinc.com had 2nd quality silnylon that works just fine for anything at prices that challenge local fabric stores. The ripstop available at some Walmarts is heavier than either silnylon or the uncoated fabrics you will want to use for most projects, and it is much easier to sew, which means you won't learn much from it.
It is easier to start with a needle a little larger than necessary or desirable.
Good polyester thread such as Gutterman's will work for most projects. owfinc.com has better polyester if you are picky.
Use pins to hold seams in alignment. The number of pin holes is insignificant compared to stitch holes. You will seal the seams of coated fabric anyway. Free-handing is only for the expert or arrogant. Pins will help you get professional results.