oldears has got it right. A 1 mm difference in pivot point can easily be accounted for by any protractor with the exception of the expensive "arc" ones that are adjusted to the theoretical distance rather than the actual distance.
Theoretics aside, I have always believed that the adjustments for horizontal tracing angles (for which there is no universally accepted standard--there are many and all are compromises) are obsessed over. Not to mention the hundreds of dollars spent on protractors that give the same result as a $20 one. Proof of this, I suggest, is found in the success of the Viv Lab Rigid Tonearm, a short arm with no offest. Said to sound great. Tube units measure worse and sound better. Same with LPs and digital, same with belt drive over most DD. The only test is your ears.
More important cartridge adjustments IMO are SRA (depending upon stylus shape) and especially azimuth.
Theoretics aside, I have always believed that the adjustments for horizontal tracing angles (for which there is no universally accepted standard--there are many and all are compromises) are obsessed over. Not to mention the hundreds of dollars spent on protractors that give the same result as a $20 one. Proof of this, I suggest, is found in the success of the Viv Lab Rigid Tonearm, a short arm with no offest. Said to sound great. Tube units measure worse and sound better. Same with LPs and digital, same with belt drive over most DD. The only test is your ears.
More important cartridge adjustments IMO are SRA (depending upon stylus shape) and especially azimuth.