I was recently trying to fit something similar together and I'm running into anti-air issues at the moment (some of my potential opponents are known for fielding helldrakes, and possibly something else in the future, we are mostly nubcakes at the moment

).
Flakk missiles looks like a possible option, but
IIRC they are pretty expensive (although good thing that missile launchers are still nice weapons). I was thinking about maybe including Hyperios platforms, but it's pretty much putting all eggs in one basket unlike giving flakks to troops; keeps the latter free to do something else when it comes to shooting down flyers and have interceptor though.
Another idea was to add fancy contemptor mortis, but it looks like a crippling point sink for 1000 or even 1250 points army (may be an option in 1500, maybe) if taken with 2 x Keres and launchers.
It appears to me that both of these options, should thay be taken, must be screened from harm somehow most of the time, what would be an effective way to do this, or maybe it's better just to give up on those completely?
So, what do you people think about performance and point efficiency of flakk missiles (or aforementioned, erm, alternatives, for that matter)?