For icon size on the desktop, try this old trick:
requires a wheeled mouse!
click any open area on your desktop
press and hold the Ctrl key
mouse wheel in on direction to increase the icon size
mouse wheel the other direction to decrease the icon size
Spacing can be changed in the registry
WinKey+R [ regedit ]
answer the UAC prompt
look in the right hand pane for the following two Values
change the numbers that represent the spacing to what looks best for you.
The values must be between -480 and -2750
I think the default is -1175 (pixels?).
Why a negative number ??? Not sure, but in some places that indicates a resource value.
I tend to keep the spacing 'squared' - the same distance for vertical and horizontal.
Make small changes, but large enough to get an idea of what the the layout will look like when you're happy with your work.
This is a trial and error - and it's not automatic ... you have to either log off and back on or restart Windows Explorer (not sure about the latter)
To restart Windows Explorer - open task manager, scroll down to Windows Explorer, select and press the restart button or right click and select restart from the context menu.
Seeing what you see always helps members on this side of your monitor.
Here's how you can grab a screen shot that shows the issue and attach it to a new post.
Screenshots and Files - Upload and Post in Ten Forums - Windows 10 Forums