Use multiple shapes to make that one shape that you need. Also there's options to not adjust things to scale so you can stretch is along the X axis and compress it along the Y axis to make it look different.
So far I've been able to only mess around with the drop shape in the middle, but I haven't seen a really wide U shape anywhere in the Emblem pieces in the game, or the scythe-like curves on the sides.
That wide U shouldn't be too hard to make, just put a white circle down, then a smaller circle on top of it that matches the background of the emblem (I would highly recommend having a background). Move it around and resize it until the "arc" you're looking for matches the reference picture.
As for the scythe curves, I believe the "swoop" shape is pretty similar to that shape, remember to use free scaling by clicking the Right Stick to make them very long and slim.
It's kinda hard to describe how to do it in text, but I hope it helped. I'd put up a video but I don't have any video capture tech :/
I'm Commander She...Palmer, and this is my favorite egghead salad sandwich on the Infinity. Toys. -Halo 4 in an egghead-shell