Lenny2 - 7:17 am on Dec 18, 2011 (gmt 0)
I was hit by Panda in February of this year. From what I've been reading... the more you cut the better. There is a school of thought out there that it takes 50% to get hit by Panda and then 75% over-correction to get back from it.
I think that people who have been testing Panda solutions would agree to deleting/no-indexing as much of the site as possible... or even starting over.
When we were first hit we no-indexed about 2,500 pages of 17,000. Most recently (two weeks ago) we bit the bullet and no-indexed an additional 9,000 pages. So far the immediate affect is that our already halved traffic has fallen off about 20%... but, we'll see what happens the next time Panda runs.