Yeah I've been trying more or less the same things gale. Trying to assign points to the cards in such a way that I don't end up with decimals. Have tried dozens of different ways but I can't seem to get anything.
I'm not sure about the fire/water/air/earth, might be a red herring. In tarot that is what the cards represent but I can't find any relevance to this problem.
I've tried heaps of points systems (based on card games I've found) where A=5,K=4,Q=3,J=2,10=1, or 10=5,A=4,K=3... etc as well as just A=14, K=13, Q=12, J=11, 10=1 etc... But I can't seem to find a way to do it without resulting in decimals.