I'm trying to get the spider cracks out of mine too and so is this other guy, check out these links is this far enough?? Spider Webbing
Do, 80, 180, 320. I was surprised, after I sanded with 320, it was like the spider webs just vanished. I'm getting mine painted the 21st. I need to sand around the bird logo a little more, I can still see some cracking.