Ah, ok! thanks guys! I'll order a random, generic 55mm screw in metal hood (designed for 50mm lenses, but that hopefully works for 58 too :P )
As a note: I have not yet reached infinity on the nikon-rokkor, but I'm quite close and no mirror clearance problems yet and I can shave quite a bit from the retaining ring yet. I think my early conclusion is that full infinity might be possible!