The respective null points will be at the very same locations - no matter whether 9", 10" or 12" (or anything in between). The derivation from that zero error arc however will be the less the longer the effective length of the given tonearm. Each of the respective different length tonearms however have to be adjusted for overhang and azimuth independently - according to the geometry desired.
As Jcarr pointed out in his post, several japanese tonearm designers went for very "individual" calculations in their tonearms geometry. The FR-60 series tonearms in particular should be recalculated before put to use. This will better their geometry by a magnitude. The same is indeed true - as mentioned by Jcarr - for many tonearms from the 1970ies and 1980ies (especially so, but not only of japanese origin).
Cheers,
D.
As Jcarr pointed out in his post, several japanese tonearm designers went for very "individual" calculations in their tonearms geometry. The FR-60 series tonearms in particular should be recalculated before put to use. This will better their geometry by a magnitude. The same is indeed true - as mentioned by Jcarr - for many tonearms from the 1970ies and 1980ies (especially so, but not only of japanese origin).
Cheers,
D.