For people who are strong in their non-Catholic Chrisitan faiths, they have probably been strongly indocrinated into the "Catholics are evil" way of thinking (and I don't mean "evil" literally). In order for that to change, openess to Catholicism, followed by the reading of many books, talking to people, and a great deal of time thinking, is needed.
Pointing out how Catholicism, particularly the Mass, is entirely rooted in the Bible (which is not what non-Catholics are told); pointing out the passages which stress Sacred Tradition, in contradiction to Sola Scriptura; attempting to explain the role of the Blessed Virgin in our lives; etc. will probably not change anyone's minds. There is such a huge putdown of Catholics by Protestant ministers (which I've witnessed first hand on several occasions) that's it tough to overcome that.
Then again, it may well be the start down that path; one never knows. I'm not saying don't try to explain/defend - just don't expect any immediate miracles.
I am too!