An alternative method is in-flight trimming. Trim for straight and level hands off then roll inverted and see if a wing drops. Add weight to the light wing and re-check. It should fly hands off both upright and inverted. The advantage is that this method can help show other issues such as a slightly twisted wing or assymetric flaps.

Either way, it's worth doing lateral balance. A plane that tracks straight through loops and rolls is lovely to fly.

Cheers from the Barfly.