I contacted Spreadshirt support recently with a very similar query - in particular how Google gives every product page the title of the product only. There seems to be no way of including the design name in the title. I think this is crazy really - I doubt very much ANYONE will be searching for ‘Mens T-Shirt’ rather than, say, ‘Cute Kitten T-shirt’, ‘Space Rocket T-shirt’ or whatever.
Anyway - the reply I got was this " Thank you for your patience.
I have been in touch with our technical support, and unfortunately they cannot meet our regular 24 hour response times.
We are currently in the process of implementing a shop improvement project. The changes will be rolled out collectively, most likely towards the end of the year. As a result, individual issues may receive limited support during this period, as all our resources are currently allocated to this project.
I am really sorry, but at the moment I do not have answers to your questions. I would suggest that you get in touch with other shop owners on our forum, and consult individual solutions.
Thank you for your understanding."
Very disappointing, but hey, there it is.