So I just part cked up the stuff to do CO2. What I'm wondering is can I run the hose above the lights or how high does it have to be.
Above the canopy, try and get good circulation to move it around. I don't see why you would need it above the lights, but it's heavier than the air we breathe so it'll still "fall" onto your plants.
I don't know your exact setup... but here are my thoughts. Have an oscillating fan positioned above the canopy (off to the side, above, doesn't matter). Attach your CO2 line (usually a very small line) to the back of the fan. The fan will help push that out and across your plants. Same for the shower grow.
I agree with guesswhat. A small desk fan on the floor pointing up can help keep it recirculating too.