Very nice work. Hope you don't mind, but I copied a couple of your corner post pics. I saw something similar on a reefcentral post a while back but couldn't find it again. I'll save it for posterity
An idea I saw (I can't remember where) for hanging heatsinks is run them on pocket door track. That way when you have to work in your tank you can just push them back on the rail and they're not hanging in your way. Just a though if you hadn't seen it done.