Norm,
my quest is only what sounds most real....in all seriousness. i don't have any pre-concieved notion on VTF. it either sounds best or it does not. i do think that only over time and open-minded listening and experimentation can the most ideal VTF/VTA be found.....and even then as the cartridge suspension softens over time these points can change.
i would say that with a new cartridge like the A90, initial break-in should be done in the recommended range, in this case 2.0--2.5 grams. with this particular A90 after about 25 hours on it i did do some experimantation and found 2.20 grams to be the best. but now there is 120 hours on that same cartridge.
we (Steve Dobbins, Jonathan Tinn and myself) had listened for awhile with the Garrard/Reed/A90 (with 120 hours on it) at 2.20 grams VTF. Jonathan felt that overall it was a bit sluggish and lacking 'sparkle' on top and suggested that we try to get it better. Steve was doing the adjustments and all three of us were listening. first Steve lowered VTF, it was better. then lowered it again, better. this cycle was repeated three or so more times. finally it got a bit thin on top, so we went back to the previous spot. better. then went lighter, worse. so back to that spot. now we worked on VTA. we went higher in back...worse. back to the same spot. better. then lower. worse. so back to the same spot. better. then we listened to some different cuts. it sounded great; amazing detail, body, open on top, powerful, articulate bass. then we measured. 1.56 grams. we were all taken aback.
regarding the Shindo and VTA. IMHO tt's don't have VTA, arms and cartridges have VTA. not that Shindo might not recognize that VTA can be very critical, but a particular cart and arm won't have different VTA on different tt's. other forces would account for different VTA's....degree of cartridge breakin, actual VTF, quality of set-up, degree of anti-skate. ambient conditions...etc. etc.
as far as overhang, VTF and VTA; they are somewhat interactive; howvever i am skeptical that overhang would change enough after 40+ hours on a cartridge (of suspension softening) to bother with messing with. it would be nanometers. and VTF will change VTA and SRA more than actually raising and lowering the arm a milimeter. the Reed 2P arm has a lever which allows for a 10mm range of 'on-the-fly' dynamic VTA adjustment which is great to hear tiny VTA adjustments....which we used.