That would only work if you were watching him, I think. You need to check it after 15 seconds. It will continue to darken after that.
Does he have a favorite spot in the box he goes? Maybe lay some plastic wrap down so it doesn’t get sucked
That I do not know...He has a place he generally goes, but he's a kicker. Would pressing it into the sawdust shortly after he goes work? Not sure how to stalk him quite that thoroughly.
That I do not know...
I found this doc on the info board that might be helpful?
https://docs.google.com/document/d/1quta5WLEjdO0Y_t2dAYSwN84h-LNZWxOdtVsJDKZ16A/pub