Auto-aligning images based on center subject

I'm trying to find a way to have photoshop automatically align a large set of photos. The photos are each of a different subject, but have the same general shape in the center, and are approximately the same ratio of shape: background. Advice on how to go about doing this?

P.S. I tried using the Auto-Align Layers feature on a small set of photos (6), with the common object (a square) being centered, but it kept giving me the error message "Layers do not overlap enough to detect alignment. IN general, images intended for alignment shuold overlap by approximately 40%." Not sure what I'm doing wrong, or if I should be using a different feature/tool... any advice is greatly appreciated!