@jsman If you start with the arm tube level (parallel with the LP surface) **and** the cartridge is set to the recommended tracking weight, if the cantilever isn't defective then you will be at the 92 degree 'rake angle'.
But the thing is, LPs are not cut to exactly 92 degrees. The cutter head is set up to get the lowest noise groove when the cutter stylus is replaced, not 92 degrees. It will be pretty close to 92 degrees when the lowest noise groove as achieved (this is tested thru test cuts the engineer performs after replacing the stylus). As a result, the 92 degree thing is an approximation; an average. I know this because I have my own LP mastering lathe.
The actual correct setting with thus vary from LP to LP, not only due to the correct rake angle but also due to variable thickness of the LP (100 gram, 120 gram, 150 gram, 180 gram and 200 gram vinyl). The VTA is adjustable on the fly with the Triplanar. To really take advantage of it you'll want to have a log on each LP that states the correct setting of the VTA with the particular cartridge you're using at the time. If you change out the platter pad or the cartridge this number will change (hence the log).
Sometimes the stylus isn't mounted correctly in the cantilever (IOW the cartridge has a defect). You might know this because it won't sound right set up as I described in the opening paragraph, or you might know it because you got one of those USB microscopes so you can look at it and see if its correct. So far I've not had to bother; I just set up the arm as I described and its always worked great.
