I did this recipe and used the whole bottle of flavoring. It was good. I would concur with those above that you wouldn't taste the flavor if you use less than the whole bottle. I recently made a blonde ale with real raspberries. I got a three pound bag of frozen berries at Sams Club.
To use...
I'm new to this too and was wondering. Jim Koch on the Sam Adams site shows to cool the wort by pouring over ice by the ladlefull.
I built a wort chiller but still wonder why not freeze some water in the primary or pour cold water in the kettle then dump in primary. It's gonna get mixed...