Dual Layer Visor Help?

[Fox Holiday]

I have recently started a project for a Air Assault Helmet, and do not know the best way of going about making a dual layer visor, Ive seen people use a bunch of styles but I don't know whats best. Also tips on how to get the two separate visors to stick together would be great. Also it would be great if i didn't have to have to visors inside my helmet, similar to this guys tutorial Dual Layer Halo Visor Mini-Tutorial
This tutorial would not be ideal for my style of helmet, If there is any other way of doing this please let me know, thanks.