I have the 1X3 and it works well. I also have different set ups using fogger, dripping method, and aeroponics but I find the orchids (mostly catts) respond best with the ebb & flow method. In fact, I have ordered the 2x4 a few days ago. Good luck.

I bought some large Rubbermaid tubs from Walmart and cut the sides down. It was way cheaper. I cut holes in the lids so I could use them for my floating raft.

I'm using black plastic trays that are used for mixing concrete. I'm doing ebb & flow in them growing bell peppers. They are on tables with tubs underneath to hold the nutrient. They measure about 2 x 3 and each holds six 2 gallon planters. The tubs cost about $7 at Orchard Supply.
-Hal