i have an idea...
make a vacuform table ( 10 dollars...)
and buy some BROWN acrylic sheets from your local crafts store or homedepot/lowes/walmart...
take some clay and sculpt a visor shape.
or just cut off the fiberglassed visor from your pep helm
and vacuform the acrylic.
take some gold spray paint and spray the INSIDE of the acrylic. make sure to leave a small spot in the middle for eye vision. and take some black cloth (like a semi see thru cloth)
and put it in the space.
and wala, instant visor that is actually geometrically correct!
you can easily achive the 2x visor look this way too...
i think someone already came up with this idea...
Westerfield does something like this
oh, and make sure to spray the INSIDE of the visor
( <this side....
so that the paint will look smooth and even.
depending on the type of acrylic you got, it might even be slightly reflective!