Those are 12mm six-siders in there, ten of them. The collection tray caters quite easily to ten or twelve dice at a time, but any more than sixteen and it gets seriously crowded. It would be easy enough to enlarge the tray, but I wanted to keep its footprint on the gaming table as small as possible.
The walls of the collection tray could probably be lower and still stop dice from cascading all over the table; I might experiment with taking them down to about 6mm high, which would make retrieving dice from the tray a bit simpler.
It's a bit noisy in use, but that could be easily ameliorated by gluing some felt or something to the inside surfaces*. It's probably not ever going to be a huge issue though.
Something this size would be easy to disguise as a piece of tabletop terrain — a pele tower, or grain elevator or something. I shall experiment and see what can be done.
Follow-up:I did glue some felt to the baffles and to the floor of the collection tray, and it did cut down the noise, but it had the unexpected side-effect of bouncing the dice out into the tray much more vigorously than before, so they bounced over the walls quite frequently.
I could make the walls of the tray higher, but that would make retrieving the dice more troublesome.
Perhaps the felt isn't all that necessary anyway. After all, the noise isn't all that objectionable.