This is a good illustration of how pilots traditionally have handled CDO's. It illustrates perfectly the fact that they are counting on the time at the hotel on the CDO for their sleep. If they were taking advantage of their FAR 117 mandated 8 hour uninterrupted sleep opportunity during their FAR 117 mandated 10 hour rest break prior to beginning the Flight Duty Period for the CDO, then it shouldn't make much (any?) difference "when wx or mx hits."

Bottom line... CDO's are a way around the intent of the FAR rest requirements. Always have been. If pilots have to get a significant amount of sleep during the day in preparation for a CDO, it takes away the whole reason they wanted it in the first place. It is what it is, folks. I know a lot of pilots over the years have rationalized how they can suck it up for a few days and get by on significantly less than 8 hours of sleep per night. That doesn't make it smart or safe. Well established sleep science (the same exact sleep science used in creating the minimum rest requirements in FAR 117) bears that out.