Last weekend I exposed a roll of FP4+ at ISO 125 of two females outdoors and processed it in Xtol with a dilution of 1:1. The prints I later made were phenomenal as to tonality and a lack of grain. The dilution was based on a recommendation on page 150 of Stephen Anchell and Bill Troop's "The Darkroom Cookbook"book. I highly recommend you buy this book for Extol and other developers and dilutions, for you can't go wrong with the wonderful results of their research therein.