I decided to tackle the mis-fitting F-810A bulkhead today. I came to the conclusion that instead of trying to modify the existing factory-stamped bulkhead to fit by trimming off the ears, moving them, and riveting them back on, I would simply start with a clean sheet and make the thing from scratch myself. I traced the existing fuselage opening onto cardboard, marked it up, and used it as a template to cut the part from a sheet of spare 0.032". I trimmed it, cut out the notches, and prepared it for being hammered over a wooden mold (which I'll create next).