Options for black tank flushing?

I actually use all three methods. I general a few minutes with the tank flusher works well. Periodic flushing with the flush king all ways sends out more stuff.
No need to get too worked up about it. If I'm at a dump station with a line. I dump and go, no rinsing or flushing no big deal. Particularly if I'm going out the next week. After all it's a black tank. It's whole purpose is to hold stuff, there is no point try to make it spotless only to fill it again next week!