There’s often quite a bit of overlap. I’m not sure what you mean by “you’ll probably get it wrong anyway,” but when dealing with Protestants, for instance, showing them the truth that the Church was founded with an authoritative priesthood, that the Scriptures tell us to follow the apostolic office and tradition, overlaps quite a bit with refuting sola scriptura.
Likewise, showing the Truth of the Church by explaining some of the tremendously deep evidences and truths of Christ’s promises to the Church, how it was instituted, and that it is a part of him, overlaps quite a bit with opposing any heresy (and particularly ideas of a great apostasy).
So, often, “showing the truth” just happens to refute the opposition. We show the truth of a particular matter that someone disagrees with the Church about–for why would we spend time showing the truth of something we agree on, unless we’re just studying together?
You have too generous a view of your converts. I’ve heard from ex-Catholic Mormons directly, second hand, and even through
www.mormonapologetics.org discussions bashing Catholicism freely, distorting it through the very misunderstandings or personal grievances that caused them to leave it.
This is interesting. In my experience, Mormons use a variation of the
opposite of this to claim support for the great apostasy and the loss of priesthood authority. I have even heard the opposite (that the actions of members can or do break the truth or authority of the belief system) applied to individual priests within the Smithian groups (yes, I have experience with Mormons, RLDS/CoC, Remnant branches, and Restorationists) to say that those priests do not validly perform ordinances.
If you believe what you said you do, what’s your other argument for the great apostasy?