Yes, a 6-watch winder can generally accommodate both bidirectional and unidirectional automatic watches. Most modern watch winders offer programmable settings, including the ability to set the winding direction (clockwise, counter-clockwise, or bi-directional) and turns-per-day (TPD) for each individual watch. This allows you to customize the winding process for each watch in the winder, regardless of its specific winding requirements. Here's why and how:

Bi-directional vs. Unidirectional:
Some automatic watches are designed to be wound by a rotor that spins in both directions (bi-directional), while others are designed to be wound by a rotor that spins in only one direction (unidirectional). 

Programmable Settings:
A good quality 6-watch winder will allow you to set the winding direction for each watch individually. You can set some rotors to rotate clockwise, some counter-clockwise, and some bi-directionally, depending on the needs of your specific watches. 

Turns-Per-Day (TPD):
In addition to direction, you can also set the number of rotations per day (TPD) for each watch. This is important because different watch movements have different TPD requirements. 

Compatibility:By offering programmable settings for both direction and TPD, a 6-watch winder can safely and effectively wind a variety of automatic watches, including those that require unidirectional winding and those that require bi-directional winding.