Aligning chunks to base model

[chitty1989]

Hi,
I have a project where I have multiple chunks of peoples heads that I need to allign to a base model of a head. Do you have any recommendations as to how to allign them?

Note: I have tried the allign chunks via camera method and used one chunk as the reference chunk to allign the rest. This gets me some of the way there but it still results in a little manual movement.  I was just curious if there is a more accurate method.

Also is there a way to view 2 chunks in the scene at a time. Ie. i want to view the base model and the chunk at the same time.