I was using some metal shelf supports (made by Rubbermaid, bought at HD) to mount a shelf on a brick wall and started to wonder about the correct way to do this. Where one of the support legs is longer than the other, should the longer one be put under the shelf or against the wall? Or if the shelf is deeper, should the long leg be put under the shelf for more support? My sense is that the longer leg should be against the wall and the support should be chosen so that the smaller leg is long enough to support 75 - 95% of the shelf depth. Any thoughts or rules about this? In my brief Google search, I failed to find anything definitive.