Mine is 11x14, but probably similar. Put a row of full length rods along the bottom, then an unslotted panel with little half moons, then one with notches along the top. You can drop rods along the notches on top to keep floating paper submersed. The half moon slots in the lower panel let you put short or long rods to have some spaces available for smaller sheets of paper (or film). I don't really have much use for that feature on mine, but it might well be handy on the big washer.
I've been happy with mine, but would prefer a solid, one piece panel. Sometimes the division can make it harder to load prints as the edge tends to catch.