Mustang seat armor

I am building three accurate miniatures P-51 at the moment. These kits are great but missing one key part, the armor plating behind the cockpit seat. I have scratch built them with plans from this link:

but don’t know how high up the cockpit they should be. I’m not sure if the top of the triangle should be near the top of the canopy or if the base should be flat against the floor. I was checking to see if anyone had a reference photo of this