vinylester is very strong, if the panel is .187" thick
this would be about 15% glass by volume, that would be stiff enough for a non-stressed panel. if the part is .125" thick, you will have an real strong panel.
You may want to use a compression molded composite (Sheet moldin compound). There is little to no porosity when manufactured. SMC can be made from fiberglass or carbon fiber, and the resin can be vinylester, polyester, epoxy, and other hybrids. SMC can be molded into channels or angles...
Try coating the hooks with an anit graffiti compound.
Something that the paint will not stick too.
If using electostatic to paint, use a replaceable ground wire, insted of grounding the hook.