I understand your concerns about scale appearance. I cover over the dowel with whatever finish I'm using on the model. Since I know where the pilot hole is from the plan CG, I never have difficulty finding the hole under the covering, and the mark where the screw-eye goes in is pretty small when the hardware is removed. Nevertheless, I see how a nicely done scale model would suffer from any detraction from its appearance. As to the weight, I have gone as high as 19 lbs with no problem, and I expect I could do quite a bit more. As a precaution, a model hanging right side up needs to be just high enough to lift the landing gear off the floor, so if something does give way, the plane need not drop more than an inch or so. If it's hanging upside down, I lift it just clear of the cradle I build for every model, so again if it falls, it has a soft landing.

I'm not urging people to change what works for them, just describing an option that I have found useful.