Duration of smoke is dependant on tank size and how you adjust the metering for the fluid. That metering can be electronically performed or mechanically with an external clamp. Wide open that 24 ounce tank will empty out in 5 to 6 minutes. Correctly metered for the best volume of smoke and you might make it all the way to 15, but I doubt it. Smoke fluid is consumed much faster than fuel. Less fluid passed to the muffler will generallly generate more smoke than a wide open supply. You have to experiment to find the correct flow rate.

It's nice to see you have a plane that will carry the extra fluid and not suffer in performance while the tank is full. Set up the smoke system in a manner where flying with a full or empty smoke tank will not effect the c/g. Balance the plane with an empty smoke tank and do it again with a full tank. The c/g should not change when the tank is properly located. That is very important!!

Seal the edges of the covering as best as can possibly be done. Smoke oil gets under every and anything. Bring lots of rags and some hand cleaner to the field when you plan to use it. The first couple of times you use it will be pretty neat but you'll come to hate the stuff in short order.