Scheduled Internet Guide

Such a schedule feature would be reliable in no way due to the way current operating systems maintain caches. Both, local resolver cache and browser cache will simply ignore any (scheduled or otherwise) settings changes for a longer or shorter time.

That said, it's not worth to think about such a feature. They also had to distribute a program (e.g. included in the Update Client) flushing the caches every time the settings change. So this is not really a feasible approach.

You'd have to ask Dyn directly about that - this being primarily a user to user forum.

This could possibly be done with your router's firewall, (depending on your routers capabilities) On mine you can set it to block or allow or force different DNS servers based on access rules. You can then set schedules for these rules.

Of course, this would only be turning InternetGuide on or off.