In comparing the lists of resources in the Silver Base Package and the Silver Feature Upgrade. The "Feature Set Resources" are identical between the two and it seems the difference is mostly in the library resources. In reviewing all of those, many of the additional resources in the full base package are things I don't really care about (e.g. 3 additional Bible translations, lots of commentaries, John Piper sermons, etc.). The most significant thing I see in the base package that I would want is the Carta Jerusalem Bible Reference Collection.
The features I'm most interested in are the Sermon Builder and the Timeline tool but I'd likely learn to and eventually use other features. How much should I be concerned about the difference between these two?