Compare multiple websites in one graph

I need to compare the performance of several websites.
Instead of clicking into the detail views of each of them, it makes more sense to have an overview like “All Websites”. There, however, the tiny graphs on the right hand side are not comparable since each is scaled according to its own image height.
Therefore, it would be a really helpful feature if we could have the number of visitors/unique visitors/pageviews of more than one website (selectable by checkboxes) mixed into one graph and scaled by the same factor so that you can really compare not only the development over time, but also the magnitude for any given day.
This would be great not only for own analyses, but also for the presentation of the performance to colleagues, clients etc. You just can make more sense of these lines going up and down if you can visually compare them.

Yeah, I need that feature too. How to manage this by my self? Can you recommend something?

Yup! I’ve run into the same issues. The spark lines are great, but don’t accurately show how each webpage is doing compared to each other.