So i went in today, started tacking up the cart. Took a little bit to even get the settings down for ac. Ran into a few issues. One is since its aluminum, the heat distortion is greater and now its crooked. I still have to put the top on so maybe i can pull it back. Also welding inside corners is tough as i cant get in there. Finally my bud brought up a good point in since the thing is so light, the tig and plasma are going to make it very top heavy. I might end up putting the plasma on the middle shelf to help weight. But as for the actual material not being sturdy enough, with just the few tacks i have on now its plenty strong, stable and ridgid. Heres two pics of the shape. And yes thats an old 300.