Would you use the center of gravity as reference for centering, the plain shape (xmin/xmax/ymin/ymax)? Or any other methods? Maybe centering based on your gut feeling? 

Imagine an object like this, you have to center on a poster or shirt:

[![enter image description here](https://i.stack.imgur.com/5ER8j.png)](https://i.stack.imgur.com/5ER8j.png)

How does one achieve a sense of balance when mandatory design elements are clearly unbalanced within themselves?