Susie, now you have taken the lid off the proverbial can of worms.
I am not a proponent of the golden mean theory in my work. I think it was invented as a guide for those who did not have a good natural eye for proportion. This is not to say that I have a natural eye, but to say that I lean on my own sense of design and proportion for what I do, rather than to lay everything out by the golden mean. It has its place, but should not be used as a replacement for your own sense of judgment. In this day, it is oft made to apply to guns that in all likelihood the maker never even heard of the GM.
You might take one of my guns and study it with the Golden Mean, and you will probably find features where you could apply it very nicely. However, the gun was not created with the GM, but things in the design fit the proportional 'rule'. Where does that leave us? I dunno, this is here I run out of steam.
I also like to have details that vary from the 'norm', in an effort to give life to the object, to draw attention to, or away from, a feature.
I am also testy today. Too much coffee, methinks.
Acer