Your trying to apply symbology to feature classes automatically?
If that is the situation you may be better off creating Layer Files. Layer files will save your symbols, visibility scale, and labeling.
When you create a layer file and add it to a new . mxd it will read from the same data.
Conversely you can set the symbology in the database itself.
Start ArcCatalog and navigate to your Feature. Right click on it and open properties.
There is a tab called Representations. You can add multiple different symbology sets to the feature class. You will still need to create a layer file.
We played around with this for our enterprise data and decided to go with Layer Files.