Okay so there are several options for you to try. There have been helmet EVA styled helmet where they do the entire helmet with the paper as a solid piece. After they resin and nearly complete the bondo stage they will cut out a section of the helmet and cut a rectangular visor portion and put into the opening. This option avoid the hassle of vacuum forming which I have seen dozen of attempts on you tube videos and many took about 3-5 tries to get it right. These are individuals who have everything and some. This visor is particularly hard because of the size and shape of it, doable but hard. IF you do the cut out section portion you can get a motorcycle visor and actually use almost the entire piece for the visor which people use for Mark V helmets and such it would just leave the upper portion of the EVA paper visor being untouched. You can manipulate Motorcycle helmet several ways or cut it out.