On your recommendation I snagged a copy of Primal Order, and as an exercise I'm statting up Zuggtmoy and Iuz. Alas, it's not as easy as one might hope.
We can calculate the approximate number of worshippers Iuz has, assuming they're basically all in his empire, and that he's supporting clerics based on the size of that population. He's a demigod.
Zuggtmoy has few worshippers on Oerth. Most will be on her home plane. How many is that? No idea, but maybe I can just copy the numbers from Orcus, maybe cut them down by half. She's a supported demigod on account of her ownership of the plane.
Both have minions, maybe 50 apiece or fewer. No servitors, at least one chancellor apiece -- Senshock and maybe Hedrack?
Zuggtmoy's chief weakness is that she is imprisoned, so she doesn't receive any benefit from her ownership of the plane, her worshipers on the plane, nor any base she stashed away on the plane. In theory players might be able to whittle down her primal, if they have overwhelming firepower, but they'll probably need the help of Cuthbert, or maybe Iuz (who desires her plane, as owning it would ascend him to supported demigodhood).
No ideas yet on what primal point value to give to the orb of golden death. Anthony, how did you come up with power ratings for artifacts? The orb of golden death is probably less powerful than the wand of Orcus. Maybe 1000 base? It's hard to say, and I wish the book had more guidelines. Zuggtmoy and Iuz split the cost unequally -- Iuz paid for a third or less. As far as I know, neither Iuz nor Zuggtmoy have any other artifacts.
No word yet on spheres. Iuz is definitely too young to have any spheres. No telling how old Zuggtmoy is. Her sphere is fungus, modelled on the sphere of equine creatures discussed in the book.If anybody here has more familiarity with Primal Order and the Temple of Elemental Evil, please, let me know what you think of my considerations so far, and especially let me know if you have any other suggestions, other Greyhawk deities stat'd up, or play reports using TPO with AD&D.