Turned out very nicely indeed Ralph.
Just to clarify - the red patches over the machine gun ports (not cannon ) were not warning signs. They were there to seal the muzzle openings, to prevent dust and dirt entering on the ground, but more importantly, to prevent icing the barrels and working parts at altitude.
The first rounds fired easily ripped through the fabric patches of course, and the patches (self adhesive fabric ) were replaced when the aircraft was re-armed.