I have had some success with the hardcores by making limited claims and by using their language. For example take a basic freeman premise like the idea that your name and your person are two seperate legal entities. Saying this is wrong gets you into a debate about moral philosophy, political philosophy and the power of the state, and all sorts of random legal-ish arguments referencing everything from the magna carta, UN charter, UCC, etc. However if you make the more limited claim that "according to the Canadian de facto courts a human being is not a seperate legal entity from their name" then it really narrows the discussion.
It's very important to use the term de facto court because otherwise it opens up a whole debate about what is a real court. It also allows everyone to agree about how unfair the court is and how it's tyranical and how they don't follow the proper law. Those are philosphical questions. But the part that's hard to deny even for the most hardcore believer is that yes, the de facto court does indeed follow this rule, which is different from freeman philosophy. The idea is to simply challenge that final leap of freeman logic where they come to believe that the system actually works the way they wish it worked.
There are lots of philosophical arguments that you will never get anywhere on. But a very limited factual claim is hard to deny and hopefully sheds some light to some people that their attractive argument that makes total sense to them is not accepted by the de facto courts. It's bad news of course because this was their ticket to freedom, but it's hard to deny when it is a limited claim, phrased in freeman style language, and easily verifable by posting court decisions.