Quote - @Deecey:

Alyson 2 doesn't seem to be symmetrical in the head part, at least I haven't succeeded in using symmetry in Modo. Does symmetry work in ZBrush or did you morph the left and right side separately?

Used Symmetry in ZBrush.

Modo is VERY VERY VERY VERY picky about symmetry. Because of that it's the app that I use to make sure that any content that I make is symmetrical. I played with a few apps, actually, and Modo is the only one that really complained.

ZBrush is more lenient and yes, symmetry does work in it.