Stability add-on for V1 of StarJeff's Carnifex stand

I printed the first version of StarJeff's stand for my Carnifex model. It was a nice stand, but we didn't realize how top-heavy the Carnifex prop was. That early version of the stand proved a little unstable. He later revised it, and the latest version of his stand has closer tolerances and additional material to keep the prop from tipping over.

I made this part to add on to the stand I already have printed. It just glues on the back, around the groove to give it enough height to make the pr