Update!
I filled out the head section with a ton of putty and the whole thing is pretty hefty now.
To try and go for the textured part in the back half, I'm stacking up some styrene and adding it some bits of rods to make it even more random. A lot of this will be covered up when I add in the blister parts.
Props for the Carrier! Good thing you are on Earth as it is locked into our chronal progression & you wont lose the outstanding work in the timestream.