Can you measure how deep that ring you started with was? Also, do have any idea how much was cut off the top of the ring before starting. I just picked up a roadside kettle to do this. I am trying to figure out how much to cut off top and bottom to end up with the best shape. I am also thinking of adding a stainless steel mud pan as a water reservoir.
I already have the mud pan and it is not being used anymore so I will probably try it. Even if I didn't have it they are fairly cheap at a place like Menards or Harbor Freight.