Electric dumper and gauge on the panel
In the early 1960s, Carpenter had a nice panel and had room for some extra switches to operate more stuff such as the generator, etc. International had a good gauge cluster design for soiled water tanks. My brother's trailer has 3 tanks and sometimes if you want to have three soiled tanks, (Galley, shower, and toilet), you want to have 3 gauges on the gauge panel in front of you. And then on the switch panel, you would have three pull switches to open and close the dump valves. They would be either air driven or vacuum driven. But then you may want to also have a camera mounted underneath near the drive shaft so that way you can watch thru a TV monitor on where you are positioned on the dump grate. On your switch panel, you want to have really 6 valve switches. One to open and close the dump valves and the other to advance the flushing system for each tank.