I have been using Google app engine for ~2 years now and love it. I am tasked with making a game and I wanted to use GAE as the backend. From what I understand the Channels API is meant for this kind of application. I got the tic-tac-toe demo working and noticed that each client got its own channel. After reading the documentation a little closer I noticed that this is how the system is meant to be used. I then checked the quotas and limits in the docs and... was devastated. GAE will let me at a maximum create 60 new channels a minute. That means I can only have 60 new users a minute. This is so limiting that I cannot use this API.
So my questions are:
Keep in mind that channel tokens do not expire for two hours. This means that if one client connects multiple times within the life of that token, you can serve that same channel token again, thus not counting as a creation.
But otherwise, yes, you are correct; 1 channel per 1 client per 2 hours.