If you haven't got litres of oil in your catch can you don't really need the restrictors, just over fill the sump a bit to ensure a good supply of oil.
People have spoken of the n1 pump being brittle and more prone to damage by bad harmonics, so the n1 would probably break before the rb30 pump. A few people on this forum run rb30, rb25 without a crank collar, I think the rb30 pump will be fine for 7000rpm or maybe just put an rb25 one in, due to it having less age on it.