If you are going to go the single tray route, do yourself a favor and build a spout and valve into the bottom of your tray. You can hang the edge over the side of the table, or put the spout through a hole in the table. It will make things 100x more easy and more neat than pouring 3 to 4 liters of chemistry several times for each print.

But IME you can almost always make space for three processing trays SOMEWHERE. Put them on the ground if you have to. Washing is the real obstacle. Showers are decent solutions, though probably a bit heavy on water usage.