Ref: when I bought my guitar Alan Marshall, who built it, recommended securing the strap to the nut as you suggest. And that's what I do. It does balance better than if I'd defaced the body with another strap button. But it doesn't define the overall height at which it hangs. Or the guitar either for that matter ;^)

I've now played a couple of gigs with the shorter strap, and it certainly helps with the tricksy stuff. Hopefully I can learn to relax the right shoulder so that it doesn't become a problem...