Balaclava Elastic idea?

Hello guys! I'm getting ready to start my first head, and I'm doing LOADS of research! Well, anyways I wanted to ask y'all something about the jaw mechanism. I personally find fabric elastic annoying, as it easily breaks up. Well I was with my mom at the infusion center where she gets her ivs, when I had an idea. You know those blue stretchy things they tie around your arm before drawing blood and getting an iv? Can you use those to sew to your balaclava? here is a pic...

Also how do I sew it on to ensure maximum jaw movement? Thanks in advance!

(Also, please be kind... I am only 11 soon to be 12 on April 2nd, I'm trying as hard as I can)