This is a problem with canned replies. There isn't going to be an argument that works for everyone. It depends on each person's specific objections and values. I have been catholic since birth and committedly so, yet none of the "proofs of God's existence" have worked for me. They are at best, arguments for God's existence.
I wish I could say that I had the simple accepting faith that so many of my friends and family do. I wish I could say that I'd have found my way to Catholicism if I'd been born elsewhere, but I get to have a daily struggle instead. I'd like to think it is because I am just too smart for a simple faith, but in reality I am just too proud.
What I can do, regardless of the reason, is give a well-reasoned account for why I remain in the faith and fall ever deeper in Love with God and will do so till death. What that won't do is be enough for you.
Luckily nothing I or C.S. Lewis can say needs to be enough for you. If Christ is who He claims to be than He will make himself known in a way that works for you (that is not to say on your terms however) If he isn't.. well now that is a confusing situation of un-falsifiabilty.