How about this as an approach against the seerstar/beaststar/screamerstar:
An army with
Imhotekh
Zandrekh
Obyron
2 Harbingers of Despair /w/ teleportation
3 units of 20 necron warriors
Coteaz (via inquisition)
............
With Coteaz and Imhotekh in the same list, you have about an 87% of going first (re-rollable 4+ to steal the initiative), unless you're playing against Orks.
So you go first most of the time, and when you do, you try 3 times to teleport a unit of 20 warriors within rapid fire range of the deathstar (before their buffs are up). Let's say you'll succeed with 2 of those units.
Now you've got 80 bolter shots (plus maybe a bit more odds and ends) coming in at the unbuffed deathstar. that's 54 hits.
VS screamer star: 27 wounds, 18 unsaved wounds, either kills all the screamers or some of the screamers and some of the heralds.
VS jetseer star/ beaststar: 36 wounds, that should be enough to pretty much neuter them a lot of the time?
Also, you've got Zandrekh to take away hit & run on "stars" that have h+r.
Could it work?