Thats how I more or less did mine, I bought my poly bushes from FF, the bushes did not sit as high as the original so, I drilled out the spot welds, welded a 1/4" plate to the face of the original frame bracket, drilled and tapped it for a couple of studs (like you have) welded them to prevent them from turning and the 1/4" plate spaced the bushes out to match original, then I just used a couple of nyloc nuts, good to go, Have had no issues for 4000 miles.