An ambitious project is the one in which there are high expectations to fulfill; therefore, there can be many obstacles during the development of the project. An example of an ambitious project can be to build a free shelter for homeless people in every city of the United States only by asking the citizens to provide a voluntary fee. It may be difficult and ambitious to gather all the money needed to launch the project, but it is not impossible.
Thinnest would be the superlative degree.
