Is there a way to get integration for Waila for how many upgrade slots are left in the barrel much like Jabba? If there already is integration like this, and I'm just being a noob, feel free to troll.

Well, you can shift+right-click with empty hand to pull up the GUI, which will show you how many slots are used and what's using them.

Fair enough. I remembered this about 2 hours after I posted this suggestion.