Looks great! Welcome to craftster. You're way more brave than me. I still can't get up the courage or get off my butt to make something for challenges.
If you use microfiber towels it holds a ton with very little bulk. Back it with a bit of waterproof material (I use PUL. Google it and it's easy to find) It makes a very very trim pad, probably as trim as a commercial pad. My pads go like this Bottom, one layer of PUL, 2 layers of microfiber, and a layer or cotton flannel or microfleece for comfort.
I got some great black with pink polkadots at wal-fart and some dark grey to practice with. I'm doing a sloper in the grey, and if it works I'll do the black with dots with the same pattern. I'll post as I finish.