@GretchenR, I haven't used fruit flavorings like that, but I suggest you bench test first. Put a few oz wine in a glass and add some of the flavoring and taste. Some flavorings will not work for you, and this let's you know without ruining a batch.
You can add berries at fermentation time, and it will change the flavor. How much the flavor changes will depend on what you are adding, and the quantity. One advantage of an F-pack is the flavor will probably be stronger, and it won't be fermented.
You can add berries at fermentation time, and it will change the flavor. How much the flavor changes will depend on what you are adding, and the quantity. One advantage of an F-pack is the flavor will probably be stronger, and it won't be fermented.