Multiple configurations with one viewer

In Settings > Software, create a new line, using the same executable as before, but in the settings box, put a different settings file in (the default name if none is specified is "settings.xml"), such as "settings_other.xml"

Note: This will create an entirely new settings file, so you will need to go through and do all the settings again the first time you run it. If you want it to start out with your old settings, then go to the viewer's data directory (on Windows XP with the Second Life viewer this is "C:\Documents and Settings\%*Windows User Name*%\Application Data\SecondLife\user_settings\", replacing %*Windows User Name*% with the name you use to log into windows, note, you may need to turn on "show hidden files"). Copy the file "settings.xml" to the name you will use for the settings file in Virtual World Starter to start with the same settings as before. You can then edit them after you launch the viewer, and the changes will only be saved in this settings file.

Example in action: One normal, one for sims in heavy use (with lots of client side lag)

Choose a name for the settings file, for example "settings_wl_off.xml" (Note: the file must end with ".xml", and it is a good idea to start with "settings", so that you can easily tell which files are which).
Decide whether you want to start the settings from scratch, or from your current setup. If you want to start from your current settings, follow the instructions above to make a copy of your current settings file with the new name (copy the current one, do not delete it).
Start Virtual World Starter and go to Settings > Software.
Click the yellow plus sign ("Add New")
Fill in the Software name (for example "Windlight Off")
Fill in the Program file/executable or click the "..." button to bring up a file dialog box to find the executable (for example "C:\Program Files\SecondLife\SecondLife.exe")
Fill in the Settings file (for example "settings_wl_off.xml" )
Note: You might need to fill in either Channel or Command Line, this will depend on which viewer you use. Check what the existing ones use.
Possible bug: One or two people have had trouble saving at this point, or the save has appeared to have worked, but then not been reflected in the main window. If you have this problem, please contact me so that I can track it down.