I'm not sure if there is a supported way to handle this or not, but I was able to get this to work with a little hackery.
From the Google Doc that you want to make the copy link for:
- Click the File drop down
- Click the Make a copy... option
- Click the OK button
- When the new window pops up, quickly copy the initial URL before it redirects to the copied document. This is the link you want.
From there, I removed the
&token URL parameter, and the rest should be self explanatory and can be adjusted as necessary:
Obviously, the user who is trying to make the copy needs the appropriate privileges in the sheet to do so.