Jim, I just programmed a new Intermatic 620 yesterday. I'm pretty sure that I came across a setting that could be a certain minutes before or after dusk or dawn. So set Event 3 and Event 4 for your scenario.
Either I never noticed that before or they've added that setting on newer models, or maybe I don't know what I'm talking about.
Starry Night Lighting
"Always look on the bright side of life."