The cardboard template was too flimsy to be depended upon; FRP's better.
Here are the 3 stages of making the top panels. The precision I was seeking is really not necessary because the foam and upholstery would conceal a lot of flaws. But why not do it right?
No portion of this page, text, images or code, may be copied, reproduced,
published or distributed in any medium without the expressed written permission
of the copyright holder.