details ... consider lay all your shit out in a line long way figure out what size piece of vent (probably square in your case) you can fit your shit in ontop of a piece of tempered glass that will hold the heft of all your lights and give ya a 2-4" gap all the way around your equipment .... lay your equipment on top of the piece of duct and trace around its "footprint" on to the duct with a sharpie put all your lights back on the piece of glass cut your holes slide the glass in the vent put a reducer on one end to 8" get a nice 8" fan to put on it and some flex conduit and pump the heat else where just my high thoughts