teffy - Good point, which option you go with should be influenced by which quanta you're likely to have enough of to buff every round. That's why I wanted to make these charts in the first place; for instance, even though a Steam Machine will consistently do more damage, a Fire or Forest Spectre is still more efficient in terms of damage per quanta.
jmizzle7 - You could make the same argument about Lava Destroyers and Heavy Armor. One is 5
and 1
for a 7/7 creature, the other is 5
and 3
for a 6/9 creature, and from that point on, the same math applies. The fire/earth option is still cheaper and deals more damage.
I've already added Forest Spirit/Spectres, Fire Spirit/Spectres, and Graviton Fire Eaters/Firemasters; I'll add the un-upped Steam Machine and Steam Machine/Rage Potion combo.