im running a 6" vortex450cfm 24/7 and 6" exhaust duct on a 4'x3'x6'h cabinet

but yeah you should not have much a problem if you keep a steady supply of cool air. when you do a test run on heat check the temperature in all spots of the room, the back corner, right under the light, above the light, at the fresh air intake, outside the intake, ect and compare everything