I lived in my RV for about 5 years: 1 year off the grid, 2 in an RV Park, 1 in a rented side yard, and another year around and about BLM land and such.
Sure, when you have access to facilities use lots of water. But if you cut down on that you'll last much much longer. You def want plenty of liquid in the black tank but there are other ways that liquid already gets in there, think #1. So how much water do you really need to flush #2? Probably less than you think.
Now my tank was not long and skinny, it was 40-50 gallons and probably 10" deep, more or less square otherwise. I never had problems draining it, just rinsed it like you all do.
CM
