Does your wall go up to just below the chimney vent or all the way to the top? Then the ramp starts at the back of the grid to the top of the wall? I had contacted Bill Mason and he suggested the wall at the back of the grid, up to 1-2 inches from the bottom of the pan. It may literally be trial by fire here soon, as I have almost 100 gallons of sap collected that needs to get run/reduced to reclaim some bucket room.