Last I checked, the difference between cooked and raw was something like 100 gp...but that was a while ago, so don't quote me on that. Lobs are most cost effective, but will take you quite a while especially once you hit 90. If you don't mind 90-99 taking a rather long time, then stick with lobs. However, if you do lobs to 99 playing 6 hours a day tops...it'll take at least a month to get 99 cooking. As for xp an hour, I could do about 1k fish per hour, so take xp per lob x 1k and there you go.