More accurate.

To make it more accurate I lathed out the body. I also made the sub's turret by stacking up lays of Lazar cut acrylic and filling it with car body filler.

trying to keep it equal.

I used a polystyrene ball which I then covered with milliput to make a solid surface to sculpt onto. I dusted the milliput with toulk powder to stop it sticking to the rolling pin. I then added the side flaps out of styrene. I scraped my scalpel into the milliput to make the sculpy stick to the milliput. I then kept sculpting and measuring to keep it symmetrical. I took photo's of it a couple of times to compare the symmetry from a different perspective. As the camera flattened the image some times mistakes are easier to spot in this way.

Keeping it symetrical.

We found it really hard to keep the sculpt symmetrical. I tried to sculpt it again using a better armature technique.

New.

This is the new and more accurate sculpt. I'm doing tests with stippling on resin with brass powder or spraying black and dusting on brass powder.