What angle should I set the VTA on my VPI turntable?

@lewm, using a USB micoscope to set SRA is very accurate. You take snapshots and measure with a protractor to a reference line that is perfectly horizontal. I use a laser level. The toughest part is holding the microscope fixed in the right position without any wobble. Once you have a microscope stand figured out it is a breeze. 

I go with Michael Fremer on this one. SRA 92 degrees as seen with a USB microscope. Otherwise set the arm so that the mounting surface of the cartridge is parallel to the surface of a 180 gram record. You will have to go pretty far ( over 3 degrees) one way or the other to make a difference in sound quality. It is not as critical as it is made out to be although I think people with more expensive line contact cartridges should try to be as accurate as possible. If they spend 10 grand on a cartridge they can plop $300 down on a USB microscope. 

@dover , I definitely agree that VTA should not be used as a tone control.
However, I think the rest of your statement may be a bit on the flowery side. Most people, myself included can not hear a degree or two one way or the other and that is probably within the degree of error of the lathes anyway. I am a set it and forget it kind of guy. But when I set it it must be right on the money, as he slams his fist on the desk for effect:-)

@lewm , amazing that many people flunked out of geometry isn't it?
I already have the microscope and the set up so why not use it? It makes me feel better knowing I am right on.......even if the records are not:-) Trust me on this. I did not flunk out of geometry. That stereo cabinet I showed you was designed in my head. There were never any plans, just a list of measurements of such things as records and all the equipment. 

millercarbon, then you need to adjust your VTA with each record as they are all a little different and you think you can hear it. Knock yourself out.