Yes 24 bit is about 12 bits more then vinyl needs ;-)
And you could of course set the gain manually and then (not)worry if both channels are equal but...There is no way to check if your needle, cartridge and preamp is 100% accurately balanced.
It is very strange that that going from a very inaccurate, but in some respects beautiful, medium like vinyl, people can then get very eh precise (read neurotic, no I don't mean the OP but in general) when recording it.
Just balance by ear!
Vincent, Amsterdam
https://soundcloud.com/thesecretworld
Babyface pro fs, HDSP9652+ADI-8AE, HDSP9632