Does what it's supposed to, and it's quite customizable Rated 5 out of 5 stars

I had previously written that the pop ups wouldn't show, and that the time settings aren't flexible. These 2 aspects turned out to be false. That said, the addon really does work well, and the amount of customization is pretty good. The only complaints are very minor. In my opinion, the alarm pop up could be a bit more friendly. It's not ugly, but it could be a bit smoother. But maybe that's just me. Other than that, everything seems pretty great. I recommend it.

This review is for a previous version of the add-on (1.9.9.1). 

Notifications and alarm times

Hi there - the alert slider in the bottom right is just one method of notification. You can set any event to also have an alarm window popup at the specified time, which I think is what you're looking for. As for the hours, those are just some pre-determined defaults. You can actually enter in any time (hours or minutes) that you want (like: 10:57 PM).
Hope that helps. Thanks for the feedback.
Tom