How does the flowrate actually compare to stock as well as those of after market (koyo, etc...)? I know that if the volumetric cross section was the same then flow would be cut in half (all other variables being the same). Also how much more cooling does the double pass provide with the larger volume of water being at a time (thermodynamics: Takes longer to cook a 20lb turkey then a 10lb turkey)? Anyways it is a great idea and I'm glad somebody has the means and ingenuity to accomplish such a feat.