I would think that fan trick would work just fine. CO2 is heavier, but its not like you are spraying lead around the room, lol.
I use 6-7 because I found for my size room that is all that is neccessary, you could use less or even more....btw how big is your room? I'm sure there are guys/gals here that have that bitch wide open because of the size of room they are rocking. Also remember, you spray too much co2 too fast, and you'll freeze your regulator. If you see the outside of the regulator icing up, you need an inline co2 heater or you'll bust that regulator and all your co2 will spray out in a wasteful fashion.