For the palm oil, check out this website:
http://www.claviaryonline.com/pollypalmoil.html
It explains near the bottom how much to feed, and you may want to try getting the smaller bottle first. This stuff helps gives the greys vitamin A, and increases the brightness of their feathers. I've never used the stuff before as I don't have a grey (or any larger parrot for that matter), though someone recommended it from another site, and said it's somewhat more close to what they would be eating in the wild (the palm nuts that is).