Pete-
I have used a competitor's product, the Valterra Flush-King (link
here), for several years. It worked very well on our former Class C. Per my rough estimate, it puts about four gallons per minute into the sewer pipe.
Unhappily, with our current coach I need a straight clear fitting, which Valterra does not offer. So, I tried the Camco Dual Flush (link
here), which appears to be the same as the "Pro," but without the attached valve. I was disappointed with the throughput- only about 1.5 gallons per minute. The extended rinse time made the Dual Flush less useful to me.
I did try to bore out the valve in the Dual Flush, which resulted in a leaking valve. It was worth a try.
I've continued using the Flush-King, but directing the outlet hose out the wet bay door, instead of through the floor.