One other thing, you want long contact time in of the FWH with the 160 - 180F wort. 45 minutes to an hour, with more like an hour being better. This is a similar time to what one does for a late hop stand after he boil.
Some think the hop oil compounds will react with the sugars, survive the boil, and then the yeast will consume the sugars. Don't know if that is true, but I have read that a few places.