See or search on the How To: Master Symbol Sizes - Pin Grid & Physical Scale document for excellent information on symbol scaling (link below).
Your Style setting(s) will determine which library has priority in a sycn operation. In the example below the Amphenol Front (face) view library has priority over the Amphenol Rear(wire insertion) view library. If the rear view is preferred, the order must be reversed using the arrow controls to the right of the listing. Of course both symbols must be associated with a given component.
I hope this information helps,