First: GREAT PROGRAM!
Second: I'm using Secs to time debates where the participants see the countdown timer on a screen external to my laptop. You allow three preset times. More would be nice, but hotkeys to select the times would be better.
In order to neatly change to one of the preset times I have to blank the external screen, change times using the menu on my laptop screen, and then un-blank the external. But even nicer would be the ability to quickly select which preset time you're using by pressing 1, 2, 3 (or more times if you decide to add (maybe?) up to nine). That way you can start/stop by pressing S, reset by pressing R, and select the preset times, all without having to open a menu or blank the external screen. You could also use zero as a hotkey to blank the screen.