Rated 3 out of 5 stars

Your howto is very clear, even for a French man with not such a good English :-) just one point, you do not mention each time we have to enter an email address if it has to be the Gmail one or the one we use inTb... It does not work for me (Erreur 403 : access_denied
The developer hasn’t given you access to this app. It’s currently being tested and it hasn’t been verified by Google...), does the problem could come from this ? I put my Gmail adress every where, excepted when we have to "Add users" where I had both address, Gmail and the one I use in Tb... Thanks for your help :-) Have a nive day, Olivier.

This review is for a previous version of the add-on (0.1.3). 

Hi and thanks for Your review.

You have to enter each and every Google account which will "use" the credentials You are creating.
For example, say You're creating Example-Google-4-TbSync and You want Your app to be used by tony@example.com and fred@example.com (both Google accounts): just add these to the email field.

It's basically the Google user(s) who are granted access to Your Example-Google-4-TbSync app.

The error You got is likely to be caused by this misconfiguration. So, if You want to access Your Google Contacts under myexamplename@gmail.com, just enter this as the enabled email address.

Hope it helps.
Thanks,
MZ