Dear Peter,
I have read several long treatises on azimuth and how to set it and why to set it. Two such experts were Victor Khomenko of BAT and Brian Kearns, a "guy" who used to hold forth on the vinyl asylum and who seemed to know what he was talking about. I printed out both of their long posts on VA. Those two disagreed on a few items, but they both agreed that azimuth adjustment should not be done in hopes of equalizing channel output. (I actually wondered whether that was your goal, but I figured Almarg would have warned you off it before me, if that was the case.) Since I own a Triplanar tonearm where it is a simple matter to alter azimuth, I actually conducted an experiment to determine for myself the effect of azimuth adjustment on channel output (i.e., not crosstalk). I proved to myself that both Brian and Victor are correct. At the most extreme angles off the perpendicular with respect to the LP surface, I was able to measure only a 1-2db change in channel output, for both the R and L channels. Furthermore, you would never want to play LPs with the cartridge tilted so far away from horizontal (or perpendicular if you reference the LP surface). Doing so would obviously damage both the LP and the stylus tip, over time. The bottom line is that fiddling with azimuth is not the way to deal with a difference in signal voltage between R and L channels. Even if you could "fix" the problem that way, you would be sacrificing too much else, including in addition to increased stylus and LP wear, also minimizing crosstalk, to make it worthwhile. You should look elsewhere for your solution.