After seeing the resident expert go through two different ways of using Tau (which I love seeing, wouldn’t mind seeing more videos like that). I thought how would (one of my favourite armies, if not the favourite) would take them down.

HQ: Destroyer Lord with the already included wargear + The Storm Lord (one of the two best HQ’s in the codex).

Elites: x2 units of full Flayed Ones.
x1 unit of Guard with shields attached to the storm lord, for protection you see.

Fast Attack: x2 full units of Wraiths with whip coils (at this point it should be standard to do so)
x1 unit of full scarabs

Troops: whatever you’re happy with really, I like Immortals as they’re a little be tougher with a bit more push shooting wise.

Heavy Support: Spyder (that’s how it’s spelt in the codex)
Optional – x2 heavy destroyers or Doomsday Arks (depends on your personal preference)

The idea is to use the stormlords special rule for Flayed ones to get them [the flayed ones] as close as possible to the HQ’s of the Tau, key is here to destroy the buffering units first and then work towards the armour. Talking of which for the armour, this is why the scarabs and the spyder are making an appearance. Don’t worry about them being shot down to much as you’ll have the spyder spawning them for most of the game (hopefully).

Why the Destroyer lord and the Wraiths? Well for fear (not the special rule, just the affect) and to act as a bit of a magnet for the tau’s fire. Otherwise – unchecked – the wraiths will munch on the troops and soft HQ’s for breakfast before cutting down the elites.

Other than that your troops will be mopping up any and all survivors.