Fidelity Research FR64s Headshell dilemma

BTW there are 9'', 10'' and 12'' tonearms. My Kuzma is made
for 9'' while my SP-10 does not allow 9'' tonearm. For tonearms
with different length different spindle to pivot distance are
needed. Ergo: one can't  chose this distance as one please. 

If we do speak about scientific arguments we have to use science principles.
I can see hypothesis - geometry. A lot of very exact calculations from derived data. Although I was thought in the university that after hypothesis you have to do experiment which must be reproducible. I do see a lot of calculations. What I don't see actual measurement with test disc using dedicated setup like old days system produced by Bruel & kjaer. So I think that Japanese geometry is problem related to that we can speak a lot, make a lot figures that manufacturers are stupid. Although at the very end measurement is the easiest way to decide.

Dear chakster, the so called ''zero points'' on the record will be
on other ''points'' by Bearwald than Stevenson. That is the
whole point. Those points determine  the amount of the angle
errors made by each geometry. You may have eff. length right
but if your PS is different you obviously negate their mutual
dependance. Aka PS+ overhang= eff. length .

 . 

bukanona, the problem of the inner grove distortions is not invented
by hypothesis. The problem can be easy solved by reduction of
playing time on each side of the record. That is to say to avoid
critical part of the inner grove. People don't buy records depending
from time duration. This also means no need for Stevenson geometry.

Nandric, show me measurements not geometry assumptions.
I don't neglect models.
I am not believer in Stevenson or Baerwald superiority.