I'm not sure if you are still looking for a solution Bob...
I'm trying to do the opposite of what you are looking to do but (I think) it works for your problem.
I am trying to move my icons closer together on my desktop (outside of Fences). The fix from Microsoft that should work for me only moves the icons closer together inside of fences..
I'm on Windows 7 (not sure what your OS is). Below is the link from Microsoft. Let me know if you have the same outcome.
https://support.microsoft.com/en-us/kb/2422164
Rough steps are: Desktop right click/Personalize/Window Color/Advanced Appearance Settings/ Item drop down menu/ Icon Spacing Vertical & Icon Spacing Horizontal.