[JFreak]

There are two types of stereo instruments.

First, true stereo which for example emulate orchestra. Flute is there in the stereo image where it usually sits in a real orchestra. This I would let be wide open and if necessary modify the stereo placement within the instrument (if possible).

Second, stereo instruments that do some widening or other modulation to be stereo. This you should treat just like a regular reverb. For example instead of wide open, place one instrument to full left - dead center and another instrument dead center - full right.