I am not an expert, but am trying to figure this out for myself if I want to do it in the future, so bear with me.
As I understand it, for the right channel, for example
Right Output (Red) on Cartridge goes to Pin 2 of XLR
Right "Ground" or low (Green) on Cartridge goes to Pin 3 of XLR
Separate chassis ground from Turntable to Pin 1 of XLR
Red becomes White and Green becomes Blue on Left channel.
Using the RCA connections , Center on the RCA goes to pin 2 on the XLR and Outer on the RCA (shield) goes to pin 3 on the XLR and a separate chassis ground ideally goes to 1.
Here is a diagram from Ayre for their balanced phono stage.
RCA to XLR Phonostage
So I guess you should ideally use a 2 conductor cable with shield and connect the shield to pin 1 and to turntable chassis ground if you can.
A RCA to XLR connector may tie 1 and 2 together if it is not expecting a balanced signal. You would not want to do that for the cartridge.
I checked on my Scott and the low (shield on RCA) are not tied to chassis ground.
So, I think what you proposed is correct, with the addition that you could use 2 conductor wire and tie chassis ground to pin 1 on the XLR.
I guess the easy way is to get RCA to XLR cables and make sure that pin 2 and pin 3 are not tied together and then run a separate ground, which is common for turntables.
I am no expert, but I think that is close. Sorry for being so long winded.
For the experts - did I get it right?
As I understand it, for the right channel, for example
Right Output (Red) on Cartridge goes to Pin 2 of XLR
Right "Ground" or low (Green) on Cartridge goes to Pin 3 of XLR
Separate chassis ground from Turntable to Pin 1 of XLR
Red becomes White and Green becomes Blue on Left channel.
Using the RCA connections , Center on the RCA goes to pin 2 on the XLR and Outer on the RCA (shield) goes to pin 3 on the XLR and a separate chassis ground ideally goes to 1.
Here is a diagram from Ayre for their balanced phono stage.
RCA to XLR Phonostage
So I guess you should ideally use a 2 conductor cable with shield and connect the shield to pin 1 and to turntable chassis ground if you can.
A RCA to XLR connector may tie 1 and 2 together if it is not expecting a balanced signal. You would not want to do that for the cartridge.
I checked on my Scott and the low (shield on RCA) are not tied to chassis ground.
So, I think what you proposed is correct, with the addition that you could use 2 conductor wire and tie chassis ground to pin 1 on the XLR.
I guess the easy way is to get RCA to XLR cables and make sure that pin 2 and pin 3 are not tied together and then run a separate ground, which is common for turntables.
I am no expert, but I think that is close. Sorry for being so long winded.
For the experts - did I get it right?