I've been doing more research on fiberglass. I learned that when drilling holes in fiberglass you have to use a countersink so it won't crack the gelcoat. How does a countersink prevent cracking? If I have a hinge and I drill a screw through the hinge and into the fiberglass would it cause cracking? Also people will drill the holes with the drill in reverse. Will that change how the holes are made in solidworks?