I'm not sure which Paterson Print washer you have or are planning on using.
I have a Paterson Print washer that can wash up to 11X14 inch prints. It does not use much water and is ok if I don't have a lot of prints to make. It looks like a modified printing tray. It can only wash one 11X14 inch print or 2 8X10 prints at a time.
I don't think it is as efficient as a Gravity Works print washer that I have and that can wash up to 10 16X20 inch prints with very little wasted water.
Not sure if you could find this type of washer in your area, but they look like a large fish aquarium.