My little ones honestly HATE the sound of the Velcro, so I have made all of their harnesses with parachute clips. Since you already have a pattern you are wanting to use, you may not be able to incorporate them into that style, but I find they hold up better with use as well. (No fuzzies or hairs to stick to the velcro). They're not terribly expensive at fabric stores either, I'm sure better if you buy bulk.
Just a thought.

Good luck!