I agree that the IUCN recommendations will be helpful. My understanding is that they should be out soon, and that will be helpful.
Your question about what should be included in terms of quantity and quality is a bit of a struggle for many countries. I think it would vary for each ecoregion and ecosystem in terms of the amount of threat and the type of threat. I don't know that there's a general answer. I think it would be specific to a particular area.