First, don't use plexiglass or acrylic. Use petg. I can be found on amazon in 12x12 and larger sheets. Plexiglass requires pretty high temps to form and acrylic is very brittle after being formed (the reason I mention acrylic is lowes and Home Depot carry sheets of it, don't be fooled into using it).
Next, yes a heat gun is more than adequate to heat petg to elasticity, but the EVA visor is exceedingly large, and getting the whole sheet heated at once would make the job very difficult, if not outright impossible. It could be worth a try, but be prepared to fail without the right tools.
Clear worbla may be a workable option though- but then again, it may be exactly as frustrating as the reasons I stated above.
Source: I did this. The pics in my thread here probably don't work anymore though... my instagram or Facebook page have pics of both. They're both @roshprops, and the pics will be a couple years back on both