I used double-time to make 30 minutes into 15, and I run this at 15 frames a second I think. We don't need any more.
About promotion tricks, Ptoing is the one blazing at them, I just use CTRL for color-picking, [ , ] for going through the luminance ramp, f2, f3, f4, Alt-f2 for Paint Mode, Darken Mode, Lighten Mode and Dither Mode respectively ( Ctrl-T for options ) and of course my hand hovers over the undo combo (Ctrl-Z) almost at all times. That's it, really. Double-click on a color on screen to edit its rgb or hsl values as I said, and I'm set, for one.