1000pt list against necrons/tau

[scorpio]

Hi all, I'm having a battle on Tuesday against a couple of friends who play tau and necrons. It's going to be a free for all, not competitive, just a bit of fun. Anyway here's the list I have come up with:
HQ: Hive tyrant w/ wings + two sets of devourers - 260pts

TROOPS: Tervigon w/ adrenal glands, toxin sacs, catalyst and onslaught(to be swapped for biomancy powers) - 210pts
10 Termagants - 50pts
20 hormagaunts - 120pts

FAST ATTACK: 20 gargoyles w/ adrenal glands + toxin sacs - 160pts

HEAVY SUPPORT: Trygon - 200pts
Total = 1000pts exactly

So what do you think? Any improvements, tactics on how to be used etc... Is well appreciated. Thanks.

[scorpio]

Bio andy should be biomancy

[scorpio]

And aswell, title should be list not lost. ( sorry make a lot of typing Errors)

[scorpio]

Edited the original post so it made a bit more sense. I'm assuming people think that the list is fine as no one is replying? If anyone does see any improvements that could be made then let me know. I will write a report after the game to let everyone know how it went.

[FTGTEvan]

Looks pretty solid to me. You've got two pretty tough opponents with lots of shooting, but you have a pretty good numbers for 1k, and 3 MCs, so I like your chances.

[scorpio]

Thanks, I was hoping to swarm them with multiple big targets so that at least some would get there alive. It should be a fun game regardless.