I just got a dozen of Д305: these Russian Ge diodes are rated for 10A (50V reverse) with a bulky screwable black-painted body. They were cold-tested at 2.1A (the max of my digital PSU) at 0.38V (two outliers at 0.4V), which is the performance of the OC31 at only 0.5A. They are not cheap, but not very expensive either (for what these are).

The nuts are missing but are claimed to be "metric" and easy to source (M4?). At 2A, and assuming 0.4V drop, the diode would dissipate about 0.8W which should be easy to sustain without extra cooling. For a diode bridge, I suppose I'll make 2 pieces of copper with a few mounting holes (+insulation), as well as a couple of 4mm holes to screw the diodes.

I think we have a winner here :-D