Easier Life with new Litter Box?

I am building a prototype for a new litter box.

When I get the money.

My idea is to use a covered plastic storage container, a large one, with a drain hole in the bottom and a supported screen of any sort inside the litter box that fits into the inside perimeter.

The litter box would be supported above a plastic tank. A fitting would run from the litter box drain down into the tank.

I will use non absorbable material as litter. They can scratch and poop and pee. The pee will not be absorbed and instead drain down through the drain hole into the plastic tank. When the tank is full, I will empty it into the toilet.

I can also wash down the non absorbable litter and sides of the litter box using a pump sprayer with tank, the liquid of which will wash into the tank beneath the litter box.

I was going to use pea gravel as litter but then found some tire rubber mulch and thought "OMG, this might be perfect." I bought a bag.

To make my proto type, I still need to come across a large plastic storage bin and something to use as the urine catch tank underneath. Gas tanks would work but they're made upright, with the spout on top, which would mean raising the litter box quite some distance to have that sit and catch beneath it. I need something squat, no more than 8 or ten inches, I'm hoping, with the opening on top.

I don't have to use anything with a pre made opening and spout, but it would be easier. And easier then to dump it into the toilet when full.

I'll pick off the poop. And, can routinely just wash the rubber "litter" and even disinfect it!

What do you think?