Is the damage of each spell based on when it is cast or when it hits? For example, if I am moving from Lunar to Solar, and the cast starts in Lunar and ends in Solar, should it be a Starfire or Wrath?
Wrong, a starfire started in lunar when its not like 1 point away from solar, will result in more damage per casttime spend then a wrath even if it ends in solar.
Only when you know that you will have to move soon, it can be better to cast a wrath since it is finished earlier and therefor the chance is lower of having to cancel your cast in order to move.
Starfire does about 5% more DPS than wrath (not sure if i remember correctly there), if you cast Starfire at 10 in Lunar going Solar then it wont be done until halfway through solar, thats -40 for starfire and +40 for wrath, wrath will definitely do more DPS at this point, You should cast Starfire when the cast is done at maybe 10-15ish Solar imo.
I will be so glad when this eclipse crap is gone. Such a broken mechanic. But as most everyone said, it is where the cast ends and if it's close, go with starfire