Also have a read of https://docs.python.org/3.5/using/windows.html and see whether it will suit your needs. I need to hear feedback on this, as we're running short on time to make drastic changes if they are necessary.

I too automate installation of absurd numbers of Python interpreters (across versions rather than machines, but still fairly often), and I haven't had any trouble being able to install 3.5 in a very similar way.