Having trays sent seems kinda sketch IMO, mostly because how the boxes get thrashed around by the shipping guys, and how easy they can crack (not that they can't be plastic welded/repaired). Two trays will protect each other a little better being shipped, and I doubt they wanna deal with decently packing less than 1 anyway. Or having single cracked ones returned all the time. That's my guess as to why some companies require you to buy more, and even then some get damaged. I dunno.. Your always better off driving somewhere for something like a large tray, or even purchasing a used one from someone local. Look around online. I got my last stack of 2x4' low tide trays for $100 for 4 brand new ones, without holes even drilled! Off some kid on marketplace. Worth the drive considering they go like 60-100+ new, if you can even find them in the shops without special orders.
Another alternative is to set a corrugated pvc roof panel over a frame with plywood, with a slight slope to one side. Then hookup a small gutter section with 2 end caps (or even a wide enough container or something like a bigger tote to act directly as the res) on the low end to catch the run off, and lead out to your drain pump, etc... Just like building a mini roof in your tent to set the pots on, with its own gutter and downspout