After reading up on on the 1200, it acts just like the 800 or the 600.
The power source for the orange wire is 12 volt and can be set to constant or variable to control either a power relay or the fuel pump directly. The setting is controlled by “fcc power relay” setting. It is set to constant on from the factory.
I used the RF wiring harness and connected the Fitech to the power relay to activate the relay during key on. I’m also using the inertia switch to Deactivate the power if the tires ever feel the need for a sun tan. I cannot recall how it’s wired though. My fuel pump(195lph) is in the tank.

The system has its own pressure regulator (58lbs). I would not run one in front of it.

There is lots of information at the FitechEfi.com/faq and also in the control console where the debugging information is stored.
So you have lots of options either going direct connect or by relay. I would think that the voltage could be shut off to the orange wire but would talk to Fitech first to get the right fcc setting.