Original STL files are hosted in thingiverse at 

http://www.thingiverse.com/thing:217267

As if by magic model a form for the visor in the original model.

Work out where your cut lines are

By looking where it intersects the main model.

Once you have the model, print it.

Spray it.

spray it some more

Have pull handles and screw locators for the peg board

Then pull in pairs out of PETG so the webbing is on sacrificial areas, having first sprayed some furniture polish for easy release.

But first of course heat it on a quartz heater hot box that you can collapse for storage and transport

remove the molds with a bit of compressed air down the side

Cut out with metal shears, its just safer, easier and more accurate than a band saw. Add magnets and drop in place.

Next step is to paint the visor, but that's another adventure...