The .dtl file I'm referring to is your standard drawing set up file. We have our values set to this:
This will only work with new drawings. If you need to change a current drawing you will have to change the .dtl file for that drawing by the method you stated above. IF you already have balloons on the drawing I'm not sure they will update. After a drawing regen if they don't update you may have to remove the balloons and then add them again for the .dtl option to work.