I'm no statistician, but my gut reaction is that you're probably comparing apples and oranges, so any comparison you come up with is not likely to be very useful. As you suggest, data distribution will play a large factor here.

In my earlier post, I meant to use the word "normalization" in a more generic sense: instead of simply scaling the numbers so they fit into a predictable range of values, you need to convert all values to "universal units" which can be compared directly. Depending on your attributes, this could be quite complex: comparing a weight versus a height doesn't necessarily make sense, as you observed. Those "universal units" might not be inches or pounds; they might be "deviation from average" or something else which is unit-independant.

But the problem will still be easier if you can separate this data conversion step from the other parts of the process.

As far as getting "the right answer," I think you'd have better luck asking someone with a high level of Statistics skill.

Alan.