I think it depends on the rig that you are using.
A very tolerant cartridge (one renowned for excellent tracking) will make it harder for us to judge an optimal A/S setting (apart from clear visual indications that we’ve gone way over the top with A/S).
Personally I would never use a cart without A/S because it will cause asymmetric wear on the stylus which, eventually, will become a far bigger problem for your records (and listening pleasure) than any cartridge mechanical issue.
If you are comfortable with these caveats then it becomes a matter of individual choice.
Regarding Balance there are many possibilities. For example -
- The cartridge can be naturally unbalanced. (Not severely, one would hope)
- The electronics can be unbalanced.
- The room can be unbalanced.
- Your ears can be unbalanced.
Always check the last one first ;^)
All the best,