Hey Chef...:ciao:
Congrats on your new 1K but unfortunately I don't think your fan solution is going work very well long term. In the summer it's going to be a whole new ballgame to keep it cool. I've got a 1K and a 6 bulb t5 fixture in a 2x4 closet and with some very robust ventilation and a/c in the summer I can keep temps in the mid 70s year around. If you can put a hole in your ceiling you can put a strong fan - 6" or 8" preferred - and you'll pull all the heat off of the light no problem. I use a 6" 630cfm fan because I have a carbon filter first in my ventilation chain but I'm sure I could get away with closer to a 400cfm fan if there wasn't a filter loading down the airflow. I have my fan mounted in the attic and a 6" hole in the ceiling of my closet to run duct thru and it works great. I suggest that you go with the strongest fan you can afford because you can always use a controller to back off the fan speed if you have too much and it's always nice to have some headroom.
In the winter when temps are in the mid 60s in the bedroom with the grow closet I can keep the closet door closed and temps stay in the lower 70s. As temps heat up I have to open the closet door to pull in more cool air and in the dog days of summer I gotta use another fan and blow cool a/c air into my closet thru a piece of duct to keep temps in line. 1K's in a tight space are sure a challenge but the penetration power that you get from them is very powerful in such a small space. If you can keep all of your budding within 36" of the light you'll have rock hard dank...
:aok:
Peace~!