I'm a lawyer. Aside from academics, not a lot of people practice "constitutional" law since it really is a byproduct of a bunch of other areas of law, most notably, criminal, followed by employment, followed by HR. Any employment lawyer is going to have a background on the relative constitutional applications. Again though, outside of academics, one does not "practice" constitutional law, as that would be a weird hybrid of employment, criminal, and human rights.

.... Go to an employment lawyer.