Thanks for the pointer. We are indeed aware of PV Output. In our paper on validating the solar model in Europe (free to read here), we used PV Output, PVLog (a similar service), and a dataset from the UK government. We limited ourselves to Europe in that paper due to accessibility of data, but are currently working on global validation of our model.
We are currently working to develop specific correction factors for Australia and the US, and hopefully for China and India depending on the availability of actual renewables output data. Beyond that, we are developing a more general correction method that can be applied anywhere, including places with no existing wind and solar industry.
More details in due course...