I don’t have any measurements handy but when I’ve played with these valves, I finish them so the tap handle just clears the side cover and is in line with the opening when closed. This way the tap doesn’t have to be opened when removing the cover.
At first glance, I thought you had cut double threads but then realised it was the original part in your photo. When making a shutoff tap once, I had to cut single threads as I had no way to cut doubles.
