Thanks for the information guys. Maybe I now have more questions.
When building a padded cable, and using the calculator referenced above, do I enter the input impedance as what the source is(in this case, the MixPre) and the output impedance as the what the desitnation would be(in this case, the unbalanced 1/4" on the H4n)?
As far as I know, the tape out on the MixPre is about 25db too hot when going into the unbalanced 1/4" inputs.
There is a cable that a lot of people have bought to achieve the desired results: http://www.sescom.com/product.asp?item=LN2MIC-ZOOMH4N-6 I think I would prefer to make my own cables(to learn how to do it), but I could always go this way with the Sescom cable if I am unable to do it myself.
From my research, it is always preferable to use the unbalanced inputs on the H4n over the XLR inputs. However, the tape out on the MixPre is still too hot and you have to knock down the signal. The goal seems to be have the gain settings on the Zoom in the 27-30 range. This seems to be the Goldilocks zone for clean sound using this combination. Here's one guy's approach http://www.danmccomb.com/posts/987/connecting-zoom-h4n-to-sound-devices-mixpre-part-ii/ with many people using his exact approach or similar. I just prefer to roll my own cables.
Again, thanks.