Is it possible to change or override the default keyboard shortcuts in Finder?

Solution 1:

You could try to remove the keyboard shortcut from Finder, as per this answer of mine, in collaboration with @Arjan:

defaults write com.apple.Finder NSUserKeyEquivalents -dict-add "New Window" nil

^{(not on OS X right now, replace text with actual label)}

Maybe then the keyboard shortcut for the Service will work.

Solution 2:

I had this same issue with wanting to change Finder's "Cycle Through Windows" default of Cmd + `.

By adding an application-specific shortcut in System Preferences > Keyboard, I was able to change the default *:

You can see this new shortcut reflected in Finder's menu:

_{* I changed it to something I'd never use, as I wanted Cmd + ` for another purpose.}