Sticking a 1000w light into a box is a challenge for sure. If you can control the temperature, however, you will benefit greatly from the intense concentration of light. I keep my cab from becoming an oven with intense exhaust suction and a small window mount air conditioner mounted to the back of the cab. The ac does a bit more work than I would like, though, in keeping the light from cooking the plants. If I were to change it, I would drill two flow holes so that the light can be completely enclosed in a tube with a heavy fan blowing in and out. I currently have a computer fan blowing in on it as an assist to the main suction fan mounted on back of cab to carbon scrubbber. This works well enough, but isolating the light's airflow would be how I would do it now.
I would recommend using both fans on an enclosed tube system if you're gonna use such a big light in a small enclosure. Just get one more fan to create a passive suction in the box itself completely independent of the light's atmosphere which should be well isolated by a closed tube system... It seems drastic, but the heat caused by 1000w hid in a cabinet is no laughing matter... as I'm sure you already know. Do that and keep the tube as far away from your plants as you can.