I want to design a system comprising of two two way data Transfer: Standalone trusted PC with 2 NIC cards, Internet untrusted PC with 3 NIC cards, Data Diode and Fortinet or any Deep inspection firewall.

One chain is for one way data transfer from Standalone PC to Internet PC using Data Diode.

Second chain for one way Data transfer from Internet PC to Standalone PC via Deep inspection firewall like Fortinet which allows for transfer of files using TFTP.

Can someone post necessary hardware, software configuration, physical connectivity of ports and wires, sample IP and screenshots of possible to make this possible.