Not really feasible to put the ozone generator before the carbon filter. When I mean it's being exhausted outside, I mean the air leaving the ozone generator is exiting the house through the roof.You'll never regret having extra odor control. If one fails the other hopefully won't.
I use both in a smaller greenhouse that is out of site, but within 100 ft of my neighbor. The ozone generator is put before the carbon filter that is outside. It has 20 feet of ducting that has the ozone at the beginning so it gets mixed for twenty feet, then goes into a sound baffle box and then into the carbon filter. You can't hear or smell it until you get within 30 feet.
Some people are wise to the ozone to cover up weed smell, so having it before the carbon filter eliminates that.