Hey there!
Hopefully you got your answer by now, but if not maybe I can help! Not sure if he did it for all of his helmets, but with his Firefall helmet that I purchased, Ag provideed a template that can be printed out and used to trace the shape of the visor onto a visor sheet to make a more accurate shape out of it. Ypu can get visor sheets from a few different Etsy sellers for around $20 a piece.
If that doesn't work out, I know he provides visor buck files with his helmets, and I know there are a good amount of people there who can do special commissions for vacuum-formed visors. One that comes to mind is the gentlemen over at Rogue Workshop. They use Titlewave Design's visor files, but I know they are open to custom commissions.
Hope this helps, and best of luck!
