If with Fosgate, all you are doing is balancing the crosstalk between L and R, then I think it is not worth it.
You need to take into account the difference in output between L and R on a cartridge.
I setup a Grado The Statement by eye (which is the way John Grado recommended along with a tip to stay away from test gear and test records) and then measured with Adjust+ Pro. The reading showed the same exact phase angle and crosstalk difference of less than 0.5 db between L and R. So in this case, both the eye and test gear method worked quite well.
You need to take into account the difference in output between L and R on a cartridge.
I setup a Grado The Statement by eye (which is the way John Grado recommended along with a tip to stay away from test gear and test records) and then measured with Adjust+ Pro. The reading showed the same exact phase angle and crosstalk difference of less than 0.5 db between L and R. So in this case, both the eye and test gear method worked quite well.