Hello Again,
I am bringing up this old thread instead of starting a new thread. I have more photos related to the subject, "Mount a Box to Your Headtube".
Before:

The Type 10 had a 1982 Suzuki fairing, which wobbled side to side, and had several large cracks. It was not good for carrying goods.
I had the Type 10 stripped down to the fiberglass cantilever rack:
I gave this rack a touch-up with some fresh paint:
Next, a plywood sandwich was made for the rack. I used plywood from furniture, so it fairly high grade. There is a top and a bottom, with 5 1/2 inch by quarter twenty carriage bolts to hold them together:
Photographs from different angles,