The body weight has nothing to do with neck dive, in my experience. I don't own an SG (anymore) to measure the thickness, but I believe they are typically in the 1-3/8" range. My Diamondback measures a healthy 1-3/4" and is also slightly larger overall than an SG. That extra 3/8" should add a bit to the weight, I guess. The body wood will obviously vary in weight, as well. Mine is a fairly heavy alder and dives like crazy. Possibly due to my choice of strap button location. But, it's too late to change it now. I probably won't be playing this guitar standing up with a strap much, if ever, so it's not a major concern. Anyway, I still think the "pregnant" SG is one of the silliest things I have ever seen

.