Commander Gree Visor

Just out of curiosity, how would one go about making one of those. Mirror tint the inside of an already green visor? Mirror tint a regular visor, and then lay some green tint on top?

I bought a football helmet visor and a mirrored insert online for my clone helmet a while back. The visor is clear and the insert just attaches behind it. Depending on where you live you might be able to find them locally but none of the stores in New England sell them so I had to venture out for mine.