I’ve been surfing my pyro for a while now in Nova Scotia. Here are some tips for the wax and suspenders
Wax- sounds like you need to tighten your suspenders to bring the zipper up a little higher. Otherwise you can arch your back more while paddeling and put pressure lower on your chest and off the zipper.
Suspenders- they attach at the front of the suit (on the inside around the lower ribs) with velcro then run up to the guide holes just behind the zipper. Then they go over the shoulders and attach again at the inside back of the suit with velcro again.
Hope that helps