Can someone help me troubleshoot this part?

I've attached the SLDPRT file to the post. I'm very close to the right geometry. I'm just a little bit off in terms of mass and surface area. I believe the problem lies with the positioning of the holes in the hub. They aren't fully defined, and I can't figure out how to fully define them. I'm also unsure what the slanted lines in the below diagram of the part are supposed to represent (circled in red).