First, those cases are tight tolerance. You are nuts for aimlessly pounding them out instead of finding a press to use for 5 minutes.
Second, when removing anything with heat, you don't torch the object inside that you're trying to remove. It's simple physics. Heat expands the metal, so by torching the bolt it swells inside the threads making it harder to remove. It also softens the bolt so it makes them easier to break off. TORCH THE SURROUNDING AREA.
Third, fuck it..... You got it figured out.