I do not understand why anyone would go to the trouble of doing a ladder stitch when piecing GFG. I am with Jinny Beyer on this and simply piece with a running stitch (right sides together, from the wrong side). I do an extra back stitch towards the middle of the hex and at each end to secure the thread.
Maybe it's just me, but doing a ladder stitch (I assume you are doing this from the front?) would at least double, and more likely quadruple, my stitching time!
If doing a ladder stitch, I would use a thread that more closely matches the color of the patches. That way, if the thread shows, nobody notices. (Actually, I would do this when piecing also -- a darker thread for darker patches.)
Edit: Oh, I finally realized you are using paper and doing a ladder stitch instead of a whip stitch. It's so much easier to skip the paper and simply piece like any other hand-pieced pattern! If at all possible, check your library or purchase Jinny Beyer's video or DVD on hand piecing. She shows how to piece very quickly and easily. I watched her video years ago, but I think she just came out with a new book and DVD on hand piecing.
Edit: OK, checked and here is a link to her book:
http://www.amazon.com/Quiltmaking-Ha...dp/097212182X/
She has a separate DVD that is out-of-print and sells for something like $160 used, which is a real shame. However, check your library to find out if they have the older video or the DVD. It's much easier to watch her do what she explains than it would be to read a book about it!