I know it's not popular, but I recommend ironing the hem first.
Make sure your iron's not too hot. Iron the first fold all the way around and then iron the second fold. The hem will stay nice and flat for you as you 'struggle' with your sewing machine. You'll have one less thing to worry about!
And there won't be any extra pin holes.
This method has worked well for me. I can see what I'm going to get before I 'commit' with stitches!
Best of luck to you and post some pictures when your DIY project is finished!