So is this a group thing, or just you and the preacher? Because if it is just between you and the preacher, then I think it's a big waste of time. Even if it is a group thing, you're eventually going to have to just agree to disagree, because you're not going to change his mind and he's not going to change yours.
Christian apologetics is the art of rolling a dog turd in sugar and selling it as a donut.