Go with the smaller needle and hand-crank. You'll be fine.

I never changed the needle out when I did all the sewing as a teenager. I broke one once in a while, but they sewed just fine.

Ken

Also, test-sew some swatches with the same layers/thickness as your actual product ... you may need to adjust the thread tension.

Only 2C I can offer is that I ALWAYS heat seal the edges of all the nylon I've sewn. Haven't had any unravel yet....I also no only fold the edge over once....I'll fold it a second time to be certain that the cut edge is deep inside the 'hem' or 'edge'. It provides for a stiffer edge though.....but if you are making a holster for a knife or gun....well maybe that's a good thing.
Hope this helps.
CJ

I have used a sewing awl with wax impregnated string. It generally looks like crud, but so far no failures. It is as strong as it gets and if it can penetrate leather, it can certainly sew cordura. I do a lot with webbing and I am getting pretty good at it after some practice. I bought extra spools and wound them on the bobin winder-thingy on the wife's sewing machine. I keep it in the BOB and if I ever have a failure I will be able to fix it and carry on. It is a good skill(?) to know. I tried to sew an interior pocket into my BOB with my wife's sewing maching and after a package of needles and a barage of "if you break my sewing machine..." I went back to my trusty awl. Just a thought.

I suggest you have a look at Ray Jardine's website (www.rayjardine.com). He sells kits for the ultralight backpacking crowd; but he has some good tips on sewing and machine setup. He's also a very interesting guy who has pretty much done it all (backpackpacking, through-hiking, climbing, treking, ski touring, kayaking - the list is impressive!!!). I sewed one of his backpack kits and had no problems but I did have to hand crank as another poster suggested above. Unlike many things, you can always do-over by carefully ripping the stitches out (get a seam ripper).

There's a vast amount of information on the web on sewing nylon (Cordura)... you might want to google kite-making.

Good luck and be patient and like many tasks in life sewing can be a mental exercise... if you think the machine will beat you it probably will!!!