I have a 2 knob shower setup with stems. The stem ends are rounded out so they dont accept the original style handle any more. I bought some Danco aftermarket handles that utilize some allen screws on an adapter to bite into the stem end and then their shower knob slides over. They dont seem to work that well. Should I try another brand besides Danco for this application, thinking their adapter design is better? Perhaps the stem ends needs to be sanded a little more round? I prefer not to have shut the water down in the apartment building to replace the entire stems with new ones. Thanks!!