As I have said, most of the conspiracy theorists we've seen at JREF are content to establish the exoneration of Oswald as their goal and to eschew actually solving the crime as arbitrarily outside their scope or irresponsible speculation. So yes, if your plan is to give the appearance of acquitting Oswald of a crime, then the most agreeable framework is mock trial in which the Warren Commission is cast as the role of a prosecutor (which it wasn't) in a criminal case and act as the defense attorney. With that framework, the "prosecution" has the burden of proof and all the "defense" has to do is to claim to have eroded faith so much in the case against Oswald that it purportedly wouldn't stand up in court. That is -- as with nearly every fringe theory -- the proponents propose that their opponents must clear a very high standard of proof, and that they themselves are obliged only to pick away at bits and pieces of it in order to prove their case.
But it's odd that as soon as I start applying a judicial rigor to his "defense," he starts complaining that I'm asking him to substantiate too much, and that my calls for substantiation and citation have become a "mantra." So it appears they want a "trial" only so they can rely upon a supposed presumption of innocence.
No, not in the least, for the reasons we've already elaborated. First, a trial tests only one hypothesis from the hypothesis set. Second, it's tested against an arbitrary high standard. Third, the different suspects are never directly compared by the court to see which one is most indicated by the evidence -- that's just not how trials work, but it's how history works and how the authorities work when deciding which of all of them should be prosecuted. Finally, a presumption of innocence holds, which is necessary for the disposition of the accused at the end of the trial, but utterly useless in determining absolute truth.