I remember on this group how the question of finding good humidity
trays used to come up frequently.

recently I learned that the pizza industry uses a standardized tray to
ripen dough. A Google search on "dough tray" you will find lots of
examples of these for sale. From $5 used to $19 or so new. Stacks of
five. Lots of different colors, etc...

The interior of each tray measures 23½"W x 15½"D x 3"H.

Everybody who has ever worked in a pizza place recognizes these
trays. I don't know how all businesses handle used trays, but If you
have a Poppa John's Pizza place near you then hang around by their
dumpsters and try not to look too creepy and eventually they will
throw some of these out. When dough goes bad they toss out the whole
tray. Probably because it is cheaper to buy them new by the train
load than to sterilize and clean them. Dig them out of the dumpster,
clean them up and you got some pretty good humidity trays for free.