I used Orbis 1080-5 bakery trays, but they have become hard to get and expensive.
You could begin by building something different. I have built some too heavy to lift, some that were soggy, some that leaked leachate all over, some that dried out around the sides, and made lots of errors that you could repeat if you are stubborn.
Some of my other photos show earlier versions that didn't work as well as I wanted them to. This is a work in progress, so if you come up with something we can all benefit from please share it.
These photos are based on building 5 VermiChester systems: