I agree with the capt... folks might plan to carry X ounces of fuel on board, based on an ounce per minute quote at full throttle, assuming the highest possible draw, with given prop...etc. However, if you are like me, I only like to carry what I need, and not much if any more. I see no point in carrying the extra weight in the planes I fly.

Since you are looking to run smoke, I completely understand your need to figure out what you must carry, vs what would simply work, so you can fit the tanks in place without fussing later.

I went this route, with a WOT quote, given prop, on a ZDZ80, and tanked my plane accordingly. I flew the snot out of it, several flights, exactly how I fly, not WOT the entire flight, of course....and I found after many flights, I would consistently use only a little more than 1/3 the recommended tank size for a 10-12 minute flight. I then went back in and retrofit a more appropriately sized tank for my application.

Perhaps before going with smoke, go with what the capt suggests. Put in a rough guess on tank size...fly and measure. Then permanently mount what you will know work for your application and flying style.