My only comment on getting it "exact" would be to go to an auction or find someone with a working machine and check it out. Haven't seen R.O.K., but have seen regular Ark1's and 2's recently. Alas, the last auction of the year was yesterday and I couldn't go.
I know on the 2 arkanoid style spinners I own, they have the "gear mechanism" underneath, and so 1 rotation gets more "clicks" than the straight spinners like Tempest/Tron or 360 steering wheels like Turbo. This explains why the sensitivity has to be so high.
That also affects the feel of the actual games vs. a smooth spinner. The "real" arkanoid spinners have an odd drag to them because of the gear mechanism. I could never figure out why in the arcades, but seeing the actual guts of the spinner, it's obvious.