My bro bought me a "how to make wargames terrain", and i actually kept a bunch of polystyrene to do terrain with that I totally forgot about. Pretty sure I've got some filler somewhere as well so I might try that option!
The problem with my walls was texturing with sand pva. One time too much sand to pva, and the texture is too much, too heavy and thick, almost looks like a mossy wall.
Then the next time not enough sand, the glue slowly slid off, and can still see too much of the underneath wall.
I thought the formation with 2 units, and a Dominus priest, one with Powerfist ans the other phosphor was a good shout. but a bit deathstarry, and 680 points!
I would only use the breachers if using the deep strike formation.