Doctopus is a tool (technically, a Google script) that automates the entire process. Basically, you make a folder in Google Drive, put a document into that folder to serve as the template, put your roster into a spreadsheet, and it does the rest. Each student ends up with his/her own copy of the document automatically and its in the folder that you specify, shared with you.
Here is a nice explanation of the process (in two parts):
I would be happy to help you get this set up if you would like to give it a try in a class.