I know there is a guide, but there isn't really any info on which mana works best. I saw in the 'most powerful strats' thread that 6+ death mana nodes is really powerful for them. However, with the recent changes in some of the spells, what would work for them?
I haven't gotten to the eaters of dreams yet, but I'm working my way towards it in my game.
Death, death and more death. For me, the highest early priority is securing nodes to turn into death nodes. At some point a brief metamagic node to give a couple of mages dispel magic, then turn it back to death.
Summon spectre is the spell that really does the damage, since it's the only level 2 summon with a mana affinity. Grab 4 nodes and you're summoning a horde of str8 terrors every turn well before your eaters come around. The 3-turn lifespan on them just makes it all the sweeter (especially when you win and can give them promos which also heal them back up....). As you conquer, you get more death nodes, your horde of spectres gets even stronger.
As soon as you get Necromancy, 2+ Death nodes will give all your mobius witches instant spectres (at 6+ strength) as soon as they pop out of the planar gates (and well before Sorcery). Once you get Sorcery, a horde of mages with insta-Death II and combat promos will eat pretty much everything else alive.
Massed Sheaim spectres are so good you almost don't even need Eaters, but the obvious choice is Summon Wraith since you've already got the massive numbers of death nodes to make insanely strong wraiths. I usually don't even bother with a second sphere, just Death III, Combat V and Extension II are beautiful on their own (and mobility I for those that are getting lichified).
As for other nodes, your mobius witches can supply spells from other mana types, and Ritualists can do the stack softening. If you're desperate for another level 3 spell, you could probably make an appropriate mobius into one of your liches