I enjoyed watching this, but it brings a question to mind, one that I suppose has no precise answer: At what size does tray development become unwieldy? Certainly at the size David Benjamin is developing prints it could be considered unwieldy and therefore the processing machines that he uses would be of help.
The biggest trays I have are 16x20 and they are a real pain to handle even when empty. Using a color processing drum, you can go much larger without much problem. The biggest prints I ever saw from a pinhole camera were processed in a modified sewage drain pipe... pretty big.
With color, you're more limited than B&W simply because of the lack of safelight.
In an old book I have they were explaining how to process very large prints by either rolling them and unrolling them in a wallpaper tray, or by using the see-saw method where you let the paper form a big U shaped form and soak it in the chemistry.
Some others use sponges or paintbrushes to paint the print with developer on the floor...
