But isn't that just matching the levels? That would work if the cartridge channels were perfectly balanced, but they normally aren't, so you are possibly not optimizing the azimuth. The usual method is somewhat similar, you use a test record with separate left and right channel tracks, and set for minimum amount of crosstalk on both channels. For example, play left channel track and record levels on both left and right channels, then repeat for right channel, then adjust azimuth to balance the crosstalk percentage. An alternate method is to use the scope and try to minimize the phase difference.