Not too much to add, I don't much like Hive Guard...so I suggest you drop one and spend 55 points elsewhere. That way you get you ignores cover, with fair rate of fire, and get more points to spend.
You do want a second Winged Tyrant down the road...

In the meantime you can run the Tervigon as your second
HQ, just put a Thorax hive on her. That way you don't have to put 30 Termagants in a single Brood.
I like to run Devilgaunts at 2/1, or 50/50 so you can use the cheap ones as losses.

In any case, good luck, and good hunting!