[quote=@BBeast]
I do not know any proper tools which could allow such a poll to take place. In a pinch, we could use a Google Sheet or something, and trust people to only edit their own details.
[/quote]

We could also create a thread dedicated to the matter: whenever a player wants to move on, they post something along the lines of:

[indent]Turn 9 - Ready to move on[/indent]

And that would be that. 

I personally like this poll idea. Probably better than the way I've been doing it (which is: 'hmm, I feel this is a good time to move on.')