IIRC Fox brand uses a water based carrier, i would like to suggest that you buy an extra can of Fox and train with it. This way you will be able to see how the spray pattern is, you will be contaminated by the spray (prolongued exposure to O.C. makes you less sensitive for the effects because you know what to expect) you will learn it's reach and you could simulate different conditions (cross wind, temperature, etc)
Remeber that O.C. sprays have been getting hotter and hotter in the last years causing higher "knock down" power but also prolounged contamination effects and duration to the user of the spray.
So instead of one can buy 3 and practice with it under different conditions.
The cost would be low and it will give you an idea what to expect before you use it in a SD situation.