In my quest to avoid being productive, I have run a bunch more data.
I now have 49 encounters from EttDP, though just before the finale. For various reasons I won't discuss to avoid spoilers, I don't think I can get good data from the finale itself.
I also tweaked where the level jumps are; instead of doing it by eye, I actually calculated experience for a four character party by encounter.
With no metamagic, the comparison stands at
Fireball/Lightning Bolt - Preferred in 22 encounters
Energy Orb - Preferred in 20 encounters
Mixed - 3 encounters
Even - 4 encounters
Empowering each spell at the first available lever (as a wizard)
Fireball/Lightning Bolt - Preferred in 27 encounters
Energy Orb - Preferred in 15 encounters
Mixed - 4 encounters
Even - 3 encounters
James, I'm afraid that your idea makes assumptions that don't fit well with the expected damage model I'm using. I think you'd find that even with the orbs, it's very difficult to kill a foe outright, and little damage will be wasted on the first casting of the fight. But, I don't have hard numbers to back that up.
I'm interested in using what I've prepared to test other things. Next, I might compare magic missile to the lesser orbs and see what comes up.
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gnfnrf