Mike, your supposition as to the reason you couldn’t add a 10th schedule are correct. I agree that there should be a more intuitive error message and I’ll put that as a TODO. Ultimately I’d like to get away from the opaque binary settings file (which is there to provide compatibility to the Arduino/AVR version of the software) so that we can have more than 10 schedules.
As for your security settings, I have toyed with the idea of putting Basic HTTP authentication into the system. It wouldn’t be too terribly difficult. However, I would be a bit concerned about putting this up somewhere public facing. Better to secure access via a VPN.