Unsure if you're set on going the route of drilling out welds and rewelding.

While I have a slightly different setup, the issue was the same. I torched the old bushing to soften them enough to get it free from the housing and cut it at the thinest section for removal. Since there isn't a single reproduction (original rubber) bushing made for my application, I bought an oversized outside profile with a correct inside diameter and made my own by using a grinding wheel (sounds crappy but I'm anal enough to make them correctly based on the removed bushings, of course I had to make 4 to get 2 good ones) My brackets are tapered so that one side of the bushing would be smaller than the other, making it a natural starter at the fat side of the bracket for pressing the smaller side into place (think of pressing a cone into a cone). I left my bushings a little fat to get good compression once installed. Doing this type of installation allowed me to powder-coat the bracket and not destroy it to instal the bushing. I wish I had more detailed pictures of the process but didn't think anyone would care or need in the future