Scan the comments section.

You've already identified venues where the in-house writers have the experience and skill set of interest. Well, in many cases you'll find amateurs and knowledgeable experts who already care enough about those subjects to voluntarily troll the internet looking to post their viewpoint below the official article.

Find someone whose tone is collegial rather than adversarial, who seems to know his stuff, and whose natural written style requires little babysitting. Hire that person!