From the DOCS maybe people should read them first :)

Step.rc

RainmeterIniFile
This can be set to point to the Rainmeter.ini file if it is not placed in the default place (i.e. in the Rainmeter.dll's folder).

RainmeterSkinPath
This defines the path where the skins are. The skins must be in separate subfolders under the given folder.

RainmeterCurrentConfig
The name of current config. This can be used to force the use of some config. You must also define RainmeterCurrentConfigIni.

RainmeterCurrentConfigIni
The name of current config ini-file.