Hi
From a fighting perspective, try both sides the hand forward you can fight best with is your side of choice.
I'm right handed and feel more comfortable with the right hand\foot at back.. I think I'm slightly quicker with pole in that stance.. RH is power hand, LH is guiding hand in my case.

From a health and postural perspective, assymetrical movements in any sport\activity can lead to dysfunction. Look at injuries amongst some tennis and golf players as an example. For that reason I would practice the form and movements on both sides. This would also be expected to have beeter carry over to wingchun non-weapon holding movements.
Just some quick thoughts.
Interested to here others.
OB