I'm an old man so I don't understand why people treat their black and gray tanks like they contain radioactive waste. I can see it if you pull up to a dump station at a Pilot and there's OTR trucker offal all over the ground, but at a CG, hooked up to the sewer, with your rig? Just pull the valves in order and be done with it. Flush the black if you have to, but not at a public dump station with people waiting.
Also wondering why you didn't rinse the stinky slinky after dumping. That gray tank can get pretty ripe. After a while that Tupperware bin will start to attract flies.
