I think you should step back a bit and think about other options. Surge tanks are great and obviously Scott will help you with that, but what about built-in wave boxes?
Picture this: NO HOLES in the tank, superior flow, low electrical usage, no achilles heel.
What I am describing is building into the tank something similar to Tunze wave boxes. Very low to zero visual polution, very high flow, controllable flow, and if one goes bad, you still have the others. Also operational on backup battery...you could pulse them, create waves, have night mode, storm mode, whatever your heart desires. This would also free up your aquascaping so that you would not be tied down to hiding plumbing. Almost like built-in surge tanks.
Just food for thought.
