nice sump/fuge.The IC variable fans are not nessecary IMO,your better off with just standard 4" fans,I use AC ones but i hear the DC/computer fans are quieter.If you decide on some new fans,just make sure to get the DB spec for each kind and go with the lowest DB level.
As for your skimmer,i use a similiar one(CS5-2).IME with it,9" of water is optimal for it to sit in,it is imperative to keep the water level stable in the skimmer chamber with not too much turbulence.Ideally,you'd plumb the overflow return as close to the intake of the skimmer pump as possible(make sure you drill a airhole just above the water surface though so you dont get bubbles to the pump).I get a full cup a day in my 40 gal.If you need any suggestions tweaking it,drop me a PM