Calculating percentage based on values in two reports

Hi, 

I've got a dashboard, which incorporates pages from a couple of different reports. These reports are each tied to a real time streaming dataset (first report tied to "assets" streaming dataset, second report tied to "os_metrics" streaming dataset). This is due to the limitation of reports only being allowed to have one real time streaming dataset when selecting "get data". As such, I have added the two reports to a dashboard to link them together.

My goal here is to caculate a percentage (ideally visualised in a new dashboard tile) based on one value from each of the two reports shown in the screenshot below. E.g. I would like to calulate, in a new tile, the percentage that "Unique assets with" (from the second report) is of "Databases All" (from the first report).

Is this possible? (essentially my question is: is it possible to do calculations based on cards from two seperate reports, and visualise the result in a dashboard). If not, how could I architect my reports so that metrics can be computed, based on measures from two streaming datasets, and visualised in a dashboard?

Any help would be appreciated - will happily provide more info if this is unclear. 

Thanks