Basically Tahribators "Best Of" Heavy Metal build in an asymmetrical form. Little less DHS than that build, but the STD survivability coupled with this 'mechs crazy armor quirks makes for a really tough machine. You could drop armor elsewhere for more armor on the dead arm if you want to use it to shield more. Or, drop armor for another jumpjet.
After the torso structure quirks, I've had zero regrets running 1 rear armor on any structure quirked torso. As for the build, I'd put the JJ in your right leg for safe keeping, and the bottom ton of ammo goes in your head. If you're alive, you're going to want to have ammo.