That is a cute graph. Howver, Huck’s positions on social issues show that his faith actually means something to him unlike Carter who actually supported abortion. Also, to my knowledge there have been no allegations that Huck has engaged in adultery unlike Clinton who was a rapist and serial adulteror.
I think you can eliminate the second factor in your equation and it would be more accurate. Huckabee doesn’t disagree with Jimmy Carter on any issues I can think of.