The Sunset/Sunrise before/after affects the timing of it. Ex:
If sunrise is 6am and you set 30min before, that would trigger at 5:౩0am.
Delays for THEN actions happen before the action. So if you set a 5min delay before turning the light on, they will not turn on until 5min after the trigger. But, as a side note, you cannot STOP that action from happening (this is regardless of delays, just most noticeable). Once a rule is triggered it will perform all actions of that rule and you cannot interrupt that.
But... Your idea of using the other devices would work. I am trying to get away from recommending workarounds like that because many people do not have others. In any case... Assuming you have two Rules for that lighting. Something like:
1) IF sunset and light off THEN light on
2) IF sunrise and light on THEN light off
You could add that light into the other's rule as an IF it is on... Then that would give you the sunset to sunrise effect, if there is nothing else that might alter it.