The common things you'd want to do in Graphite will be easy, more complex things requires knowledge which isn't in the docs, but easily found if you're willing to invest the time in searching and reading code. Of course everyone would like great documentation; however some open source projects may not have the time for everything -- and that's ok, because its all free and full of love. Graphite is a great engineering achievement, and an awesome tool to have. Give it a try, even though it lacks documentation at this stage.