FWIW, since flare fittings on the pressure side of the 11's brake system are 1/4 inch 45 degree SAE fittings, the male flare fittings (e.g. the adapters between the frame and the flexible lines) are threaded 7/16-20. If you have one of these handy, you can thread it into the bleeder port of the wheel cylinder to confirm they are threaded 7/16-20
That's a good idea. I might just whip upto the local bolts and fasteners store with one of the tractions bleed nipples and ask for 4 normal bleed nipples that match. I bet they measure it and hand me over the bleed nipples without a seconds thought.