Consider also whether you need a Perl consultant with at least a rudimentary understanding of RDBMS technology, so that they'll not need to have the problem explained to them in detail.

This may be less important if you're going for the quick fix on temp tables only and have a well-focused description of that task, but could be really important if you're hoping to get someone for a longer-term assignment.

someone who doesn't want that job, despite adding a job qualification that would include him

They laughed at Joan of Arc, but she went right ahead and built it. --Gracie Allen