Ok, time for a complete build...we're human by definition as an Ethran.
Archivist 11/Hathran 9
Feats:
1st-Ethran
Human-Earth Sense
Archivist Bonus-Scribe Scroll
3rd-Earth Spell
6th-Leadership
9th-Extend Spell
Archivist Bonus-Persistent Spell
12th-Node Spellcasting
15th-Metanode Spell
18th-Quicken Spell
We get Heighten Spell for free using Circle Magic, along with Empower and Maximize if we want them, and with Leadership + access to Sims, all the spell levels you want to power things. Without Arcane Manipulation access, ironically your cantrips can be higher CL than your 9's, but that's ok. You'll have a LOT of spells to throw around.
Now, to get the most out of the node : use circle magic to raise your CL to 40 base, add 21 for heightening a cantrip 21 levels, add 7 for items (1 Tattoo, 1 Ring, 1 Ioun Stone, 4 Bead of Karma) for a total of 68. Cast greater consumptive field, bringing that up to 102. Now make your node. I don't have the formula in front of me, but I can say with total certainty it's at LEAST class 6, meaning free persisting and free quickening. The latter is important, as you can now cover the three GOD roles at once each round even without your cohort's input. You can stun enemies as a move action with no save or SR, buff or BFC as a swift from quicken spell for free, and do the other as a standard.
Lemme know what you think!