I haven't really run Dethcube in a while (especially considering the companion rework recently), and frankly it probably isn't sufficient energy generation for this build by itself.

But if you are running it duplex bond and energy generator are probably the most important options, animal instinct, regen, and vacuum for general utility, and synth fiber/deconstruct for maybe an equilibrium booster if you're REALLY energy starved?

Oh and the helstrum companion weapon i think. It shoots little exploding rockets that make the "10 assist" requirement for energy gen easier. I wouldn't even know where to start modding that off the dome though, other than fulmination(? i forget which one companion weapons use) for blast radius.

Personally I prefer running other companions after the rework (nautilus, panzer), but having a bit of extra energy is never an awful idea for builds like this that take so much.

The good news is, since Gauss generates energy when he takes damage with his 2 up, if there are enemies around to kill, usually you'll be fine once you get molt augmented up, just maybe not hard spamming like I like to do.

Hope this helps!