Newbie Question about Desert Tombs

[tinkthank]

Small follow up here:

I am becoming intruiged with DT, because if you can field a large number of undead summons, this is the perfect fodder answer for Poison Slingers. In normal Ctis, I get upset when my slingers poison my whole army -- but here....
Only question is: What orders do you give em, and where do you position em? Because of their lousy range, when I set them to fire closest, they STILL run out quickly and get slaughtered. Should I set them to fire and flee (and then spend my subsequent turns running around gathering them up from neighboring provs)?

Last question: What schools/spells do you research? I think the only spell I can think of offhand with death and fire is Banefire -- is that it? Do you rush for it? Is it good? I figure I would need construction soon to make Skulls o Fire -- with fire, I suppose one goes Evocation. But what good is Evocation with death??
What good is Thaumaturgy without Astral?
So basically, I am confused as to a good research strategy.
And the poison slingers. Heheh, thanks.