Well, here is the best way I've found to scale something: use the head. Let me explain... Let's use this picture as an example, because it is the best side view that I have been able to find. In the picture, measure the height of her face, from hairline to chin; we will call this measurement "one length." Now you will use that measurement as a guide for how to construct the entire headpiece.Now, apply that measurement to the headpiece in the picture; it is almost exactly one length from the base of her headpiece to the narrowest part, near the top. Also, the base looks to have a diameter that is just slightly smaller than one length. and on and on....To transfer this to Sydney's scale, measure Sydney's face from chin to hairline. This will be your "one length" for construction. Now, use the measurements you took off the picture, and apply them to Sydney's hairpiece. Does this make sense? We used this technique for doing still life in art (only with a pencil and your naked eye as your measuring device!). I can't think of any better way to describe it... Hope I was able to help some way!