I am working on a large job and I am way in over my head. 7 RTUs, This guy is having me install flex duct up to 18 inches across this massive two story event Hall themed "country style, it's a Barn". I'm at the flat roof now where the units are supposed to be placed. The framers are cutting these holes according to the boss's ideas and I'm running in to huge issues. I have resolved some but the owner is telling me to ignore the blueprint and just get it done. I got 6 18" packed in this upshoot corner three are returns right there opposite the wall and three are the main sends coming through the wall. This area is maybe 7 by 7 square and has the a frames. My question is I need to know which hole per unit is send and which one is return. Frames originally mounted were wrong and ripped up because plenums were too small and now I think the new frames are spun around not like before but the owner doesn't know exactly because the guy he calls hasn't laid physical eyes on the situation. A little help?