Unless you can afford multiple starpriests, just bring them as a support & a potential backup threat.
Unbuffed they're excellent support, they're also decently good for holding objectives (possibly together with a screen of skinks for bodies)
And when your big block of skinks dies and your starpriest becomes available to buff the razordonsthey can transition into your main threat.
Also, since they're not too scary, they'l probably be allowed free reign for the most part as there's bigger priorities to kill first, allowing you to have a decent unit left at (near) maximum health towards the end of the game.