Don’t forget a good Earth ground.
And that ground needs to be CLOSE to your cage, or else it will act as an antenna for EMP.
The problem with this setup is, there is really no way to test it. We don’t know if it will work at all.
“Don’t forget a good Earth ground.”
The ground will not affect the environment inside the shielded area, if it’s a true faraday cage, provided you don’t have any other penetrations into the shield.