It's actually very simple.
The person signs the contract with their name and full address.
I only send the card to the address in the NDA Agreement.
MacPro5.1 past Catalina:
Dont see any reason why it shouldnt.
We tested a native installation way without dosdude with OpenCore and it works.
Will also work in future if you use the OpenCore Bootloader for it
and of course if the GPU is supported in the OS Version which you try to install.
NDA's are a powerful method to protect yourself and your IP. If you are concerned, add a non-competition clause in the NDA as well as hefty fines / financial responsibility for legal fees on any unauthorized disclosure.