Yes, and like I said the only thing I would debate is that it (neck dive) is a design flaw. My SG weighs in a shade under 5 pounds, and neck dives like a Mo'Fo with a slick nylon strap. A suede strap solves the problem. My SG weighs about half of what my Les Paul does, and still looks, feels, and plays great.
My only point was that Gibson designed the guitar they built on purpose, and neck dive was considered an acceptable tradeoff, if it was even considered at all. If Neck dive is a major concern for a player I can understand that, and the SG is probably not going to be a guitar they will be happy with. When I got mine there were several things that bugged me for a week or so, but once I got it sorted with a grippy strap and adapted to the instrument I wouldn't change a thing.
I bought the SG thinking it was the same as a Les Paul just a little different looking. Nope. It is a LOT different. Like it or hate it, the balance issue is part of the package. You can add weight, but that negates a major advantage for the stage player doing several shows a week looking for a bit of shoulder relief.
Also, Congrats on making your own instruments! By all means make them what you want, and I wish you all the best success in the world. I also promise not to call it a design flaw if they come in a few pounds heavier than mine!
Hey, I went from playing Les Pauls and other LP style guitars for years, so anything that's not a boat anchor is an improvement. I never bonded with the SGs I owned in the past and a large part of that was the neck dive issue. I just can't wear a suede strap. All my straps are slick seatbelt type material. However once I acquired one that didn't neck dive, it was a game changer. It's not just the weight of the guitar for me. It's the entire feel of it. The shape of the guitar, the thickness, just everything about it feels that much more comfortable to me than a Les Paul, or god forbid, a Strat.
Anyway, regarding the thickness, lets not call it a design flaw then, How about just a minor oversight? I don't think that adding 1/8" body thickness will alter the weight significantly, but it will certainly help with the neck dive.