In 1979, Noel Keywood wrote an article in Hifi Answers which indicated that the levels of distortion due to mismatched VTA could be high - much higher than horizontal tracking errors. Vertical tracking error is the equivalent, with regard to the cartridge, of the error introduced by a pivoted arm in the horizontal plane. In stereo reproduction, with the recorded groove sides at 45 degrees, both horizontal and vertical tracking is relevant.
More of the article is available reprinted in Hifi World here
There is an article by John M Risch and Bruce R Maier from Audio (March 1981) which I have uploaded here
There has been some discussion recently about optimising Stylus Rake Angle, and how it should be 92 degrees, no more no less. This figure, sometimes trotted out as an absolute, is no more than an average.
As Risch and Maier state in their article:
SRA, however, is generally 91 to 95 degrees relative to the record surface in order to facilitate lacquer chip removal... Proper hifi set up should therefore concentrate on cartridge adjustment such that the contact SRA face is 92 degrees between the stylus and the record surface. Such alignment will at least approximate correct SRA.
And another article by Keith Howard in Practical Hifi (August 1981) which I have uploaded and you can read here
