Night Lords theroryhammering

So with the new heresy box and the small amount of FW I have I'm starting to scheme how to build a force but am a bit off on how heresy games play.

Currently I have built
Sevatar
apothicary
2 HQ from betrayal at calth
contemptor with options for 2ccw or ccw + AC/plasma cannon
10 marines (just bolters)
raptor gunship
5 raptors

so with 25 marines and 5 cata termies left to build i'm debating the best options to make a working list (or at least start towards one)
I would like to try and be a short-mid ranged army with lots of bodies to take advantage of the night lords CC benefit (+1 to wound if you outnumber enemy in cc)

anyone know if a 20m squad of marines is worth it? loaded with fearless and fnp