NH35 rotor.
I'm about to build a "Seiko" diver, but the NH35 supplied looked a bit bland, I found L.A and discovered their rotors, bought the black, full size and a set of tweezers, both items arrived in reasonable time to Australia. The original rotor weighs in at 3.8gr, whereas the L.A rotor weighed 3.9 gr. I don't beleive this should affect the mechanisms' performance. All in all, easy to order, arrived quicker than expected. Next time, I'll buy a new bridge as well.