Tony - while i can't answer the questions you posted, i just wanted to say that i just found this thread for the first time, and I am really awed at your set-up. The stand is beautiful, your tank is lovely, and i am really impressed at the plumbing (I'm still trying to figure out plumbing for my tank.... I just don't get some of the spatial/technical stuff... am trying, tho!)
anyway, it looks amazing and best of luck with working out these questions!