Ultramarine Centurions

Having only recently begun to get back into gaming, I've been paying more attention to the meta on the 40k forums.  Especially for unit optimization, where in the past I've always been more concerned with what i thought looked cool.  Enter some Grav equipped Centurions.

This is the second squad of Centurions I've built, and just like the first go around, the trickiest part for me was the weapon hosing on the back.  For one thing, the instructions are only for two builds, and don't show the third model.  So your assumed to be able to figure it out from the first two.  I can do this, but it makes it a little harder to insure the arms are posed properly.