Here's How You Change the Spacing
Set a restore point and backup the registry if you want to be extra safe.
In the registry find HKEY_CURRENT_USER/Control Panel/Desktop/WindowMetrics.
The two keys of interest are IconSpacing and IconVerticalSpacing.
The default values are -1125 which represent H and V spacing of 90px (approximate).
The formula is Spacing px = - Key value/12.5 (I have no idea why it is a negative value)
I found that H and V Key values of -800 made nice spacing at 64px.
Close the registry editor and reboot.
Right click on the desktop, uncheck View/Align icons to grid then check View/Align icons to grid and they should snap to their locations.
You might want to keep a larger H spacing to allow more characters in the caption and a smaller V spacing with the captions limited to one line.
On my desktop I have 3 columns of icons for regularly used programs and files (mostly programs). Yes they take up some room but that's not a problem with two 24" monitors. Icons for always used programs are pinned to the task bar (browsers, email, windows explorer, a 2-pane file manager, Quicken). My "not used often" utilities are on the Start screen for handy one-button (windows key) and one-click access as metro tiles. The very few useful metro app tiles are also on the Start screen.
Two important icons/tiles are duplicated on the desktop and start screen, Shutdown and Reboot with only one click. This is done using Steve Gibson's Wizmo which has been around for years and works with all versions of windows.
GRC*|*WIZMO - Steve's Windows Gizmo**
Click on the image for a larger version