So, let's round off and say 30 oz. of silver at $30 per.

$900 return on a $50 investment ain't too shabby. Is it?

Yes, I noticed the lights aren't perfect but you can still tell.
When you first connect a clean cell to the wall wart, the red light glows brightly. When you submerge it in the fixer, it is barely aglow.
As the silver gets pulled out of the fixer, the red light gets a bit brighter.

I also watch the color of the silver building up on the plate. It looks like sand. About the color of sand, too.
I pulled mine out when the sand started getting darker.

My darkroom is in the basement. I can look in every so often as I go down to do laundry and stuff. The intensity of the light will give me enough information to know when to go look at the condition of the "sand" inside the cell.