I realise that there probably isn't much need for these scripts anymore but, well, I need them so :)
 
I had trouble with the -url argument. The example shows using "http:/myWebApplication1" however I kept getting errors saying it couldn't convert uri to guid, I changed the -url argument to a string and it worked.
 
Also, the EnabledForScoping property doesn't save unless you perform a .Update() on the property. (after line 169)