First, are you using a supermod or any other mods already? This will be important in deciding which way to go.
BTW, I don't think there has been an actual mod released for increasing the DG damage, so you might have to do this yourself.
Option 1) If you are using a supermod where the DG damage has been altered then you can just copy back in the Stock Version of the Shells.zon from the DG folder will revert all shell back to stock values.
Option 2) Use Minitweaker (
found here) to increase the values inside the Shells.zon file. You will also need the separate tweak files which can be found on the same page. If you are going to use MT to change your files you need to know that MT will create a backup of the original unedited version and store it in the same location as the file you are working on, your changes will not work until that backup is moved from that location. You need to be changing the MAX & MIN EF Radius in the Shells.zon.
You can go silly here if you need to but there might be adverse effects if you go too high with the shell damage.
Hope this helps.
