I agree.
Just as an example, if you have a silver wire submerged say 3.5" into solution, you need to use a FINE wire cathode (I use 24 gauge - wire out of an old, broken CAT3 ethernet cable) and even at this, that copper wire may not even be submerged 3/4" to raise the cell voltage to 10V+ which is where you want to be. Its all surface area - the more surface area of the cathode IN the water, the lower the cell voltage.
Some here used copper house wiring wire (Romex) but the normal stuff is 14 gauge. I tried and could barely glance the surface of the water with the wire before it was difficult to keep the voltage up over 10V and then any mechanical motion or a tiny bit of evaporation and the cathode disconnected from the water and now I had no clue what I made. At least with the 24 gauge wire, there is some reasonable adjustability where when you get the cell to the required minimum 10V, there's still at least 1/2" of it in solution so evaporation and mechanical vibration don't cause the cell to stop functioning for the cathode no longer being in solution if either happens.
How much more surface area does your mongo stainless bowl have compared to a short length of very thin copper wire? Right?
Are you actually measuring the voltage across your cell and if so, is it 10V+? You need to measure the voltage and adjust the CATHODE to set it to 10+V before you start the run. I don't see how this is possible using a stainless bowl as a cathode.