You can connect the ADAT connectors between the MR and the ADA8000 (out to in and in to out). These contain the clock data and the sync locked led on the ADA8000 will light up.
Then you will get 8 more inputs and outputs which show up as MR816CSX ADAT 1 etc in your device setup which you can then name as you wish for use in the VST connections
I do my headphone routings via the Cubase control room and out to a Behringer HA4700