I have done a few headdresses over the years. Most headdress models have a special brace made for them.......Your model wears a special corset that has a pocket postitioned where the hips meet the lower back and that pocket is where the paddle end of the brace goes into, straps then hold a steel rod bent to fit the curvature of the model's spine, neck, and head ..... the rod is welded to the paddle and the other end of the ros bolts with wing nuts onto a fibeerglass helmet that the headdress is made on. SO, the weight of the headdress is not carried on the head and neck at all, it is carried on the hips and lower back area.
Additionally, there is an upper weight limit. If memory serves me correctly, the toal weight complete.....including flowers, trim, framework, etc. cannot exceed 35 pounds.
Maintaining balance is important as well as periodic fittings on your model to ensure that everything stays centered with gravity.
Lastly, there is also a height and width limitation. - If I recall correctly, The height above the head cannot exceed 6 feet, Yo cannot exceed 4 feet total width, and cannot extend past the knees and cannot extend more that 4 feet directly forward or backward of the model.