Simple mod that allows user to customize Spidertron's weapon slots. Optionally adds a fifth weapon slot, and dynamically modifies spidertron recipe to require the new weapons.
I'd love a version where you can load and unload vehicle weapons like you can with player weapons - although I don't know the viability of such a feature.
I'm not sure if that would be possible without a runtime script; this mod only ever makes changes during the initial load phase. I would have no idea how to do that during the actual game.