In order to create the sample chart in your dashboard, we'll just need to use a Dual Axis after applying the "Running Total" quick table calculation which can be accessed by right-clicking one of the measures on the view and going to the Quick Table Calculation menu. After we do the Dual Axis (and also synchronize the axes) the chart ends up looking like this:
For reference, here's the help pages that pertain to the solution:
Hope that helps!
Much appreciated mate!
You have just opened up yet another field of charting and visualization within Tableau for me.
You are a legend!