Made my visor with a cheaper option.
Went to a local office supply store and picked up a a4 sized document protector, the thicker pvc type. Kind of what they put menus inside of in some restaurants.
Menu and Bill Holders | Officeworks
(I'm an aussie so the above is an aussie suppliers site for reference purposes)
After that I picked up a roll of cheap car window tint.
Cut out the window tint to fit inside the protector, trimmed the protector to fit as a visor in the helmet, glued visor in place, done.
Cheap, quick, no heating or shaping required and the view through the visor is like a pair of dark sunglasses.