Sounds like you got your wok cut out for you. 2 Tangs in a tank that size will eventually become a problem even if you get them when they are small. Im not sure what size pump to tell you to get but there is a pump head loss calculator in these forums somewhere.
http://www.reefbuilders.com/blog/200...ter-aquariums/
Just enter what elbows and 45 you think you might need and the vertical feet from your sump to your tank and you should be able to get a pretty good idea what size pump to get.
I dig the photoshoped fish tank you got in the opening.