How can I judge that a mediator is “right” for me and my dispute?

First the Mediator must be a true neutral. The Mediator must not have a stake in the outcome of the mediation, other than to facilitate the stakeholders to make good decisions. You should feel free to ask all your questions up front. Ask yourself whether the Mediator listens to you and gives you proper feedback. Does the Mediator’s education and background seem appropriate for your situation? Will the Mediator provide references, if asked? Will the Mediator go to your location or where the dispute is occurring?