Seekers have a huge weakness: terrain. They die quite easily to
DT tests, and going at I1 also means they die before getting to charge.
The way to mitigate this problem is a Slerald with the Locus of Grace. This means you'd have to replace the Masque...but she's not that good anyhow, so the tradeoff is worth it.
If you can, get the Wulfen supplement, because the new rewards and psychic powers and
WL traits are AWESOME.
(In fact, you can find what you're looking for on this page, with some digging:
http://40kpm.blogspot.com.es/)