Well, I read the book and thought DS7 was a solid level 4. After I picked myself up off the floor, we had DS7 tested by a different tester from Ruf and his scores and level of work qualified him for the DYS program.
So while I see some problems with Ruf's methodology (such as that it's fairly limited anecdotal evidence she's using to draw her lines), I think it is useful for just what you're doing with it: ending your GT denial and getting motivated to get more information.
I would never use Ruf to decide that a child was NOT HG+, but I think the book can be quite good for helping parents to realize that a child might well be HG+. So ruling in, not ruling out, if that makes sense...
