+1 for the Razorock SLOC.
Had my first shave with mine this morning. I would say it's just a shade above a Rockwell 6s on plate 3 for efficiency.
Very smooth, easy shave.
Yeah, my SLOC is just silly comfortable to shave with. I think your take on the Rockwell plate 3 is pretty accurate. I usually use my Rockwell on Plate 4 and the SLOC is almost, but not quite as efficient.