That sounds like it should work good.I actually have a 8''fan in the bottem right side of my cab also that I cut a hole into that acts as a passive intake.At the top of the other side I have another hole cut out where I put pvc tubing in,and this acts like a vent to throw out any hot/old air that is in the cab.It works pretty good as you can feel alot of air movement comming out the vent hole.Then again I have a small cab.How are the temps.with lights on?