Without going into the variations, and leaving the definition of what constitutes a “comfort verb” between you and your artist, I’ll give a simple example as I usually use it.
For various reasons I use Mix 1 for my artist Cue (my cue sends in the mixer are routed to mix 1 in the Control room mixer. Also to be clear, I use mono inputs for the mics (although that’s really neither here nor there).
In the UR Hardware Setup Window (I have this mapped to a Keycommand for convenience) on the reverb Routing tab, set the routing select to Mix 1L/R and set up the reverb according to your taste (Type, Time, Return level etc.)
The Phones 1 are hardwired to mix 1, so these automatically become the artist Phones - turn them up on the UR.
Adjust the amount of signal to send to the Reverb on the Hardware rack in the Cubase mixer console (bottom control).
I think that should cover it.