I also use a SaniCon macerator (12 years now). When I arrive at the campground, I connect my power cord, water hose and my SaniCon hose (less than 3 minutes). It's always connected and doesn't need to be flushed out when done, just cap the end and put it back in the bay. I open the grey and leave the black closed. I open the grey every time because I don't want to have to worry about overfilling the grey tank. I like long showers and we have both a washing machine and dishwasher.
I added an electric black tank valve with a switch inside the coach. I also added a switch for he SaniCon inside the coach, so I can dump when necessary. It's turned out to be very handy. About ten minutes before were ready to pull the slides in, I open and drain the black tank from inside the coach. Once the slides are in, I disconnect the SaniCon hose and cap it, disconnect the power cord and the water hose and I'm done, less than 3-4 minutes. Off I go.
Don & Mary
2014 Newmar Dutch Star - All Electric - 450 ISL
2016 GMC Canyon 4WD Crew Cab