Recommended paths for SVN VCS roots?

Trying to get automatic labelling working against my SVN repository, and hitting a brick wall. Looking to see if the way I've got things set up is recommend or not.

Assume a SVN repository of /svn/project,  with the standard layout below that (/trunk, /tags, /branches)

I set up a VCS root to "/svn/project/trunk" which is used for the builds. Everything working fine with that.

Build labelling doesn't work however. I get messages like "labelling the path project/trunk/trunk to project/trunk/tags/mytag has failed"

The labelling feature seems to assume the VCS root is ABOVE the /trunk. Is that correct?

Should I change the VCS root to just /svn/project?  This will mean changing checkout rules in build configurations so I ONLY checkout /trunk, otherwise I'll get a full copy of all tags and all branches checked out on each build.

I don't properly understand the syntax of the labelling rules. Can I set a rule to work with my current vcs root?