Overflow box vs.Strainer Fittings

[Palster]

I finally got my 135 gallon tank drilled. I drilled a hole for a 1 1/2" bulkhead fitting in each back corner of the tank plus a 1" return in the back middle of the tank. I now have the tank completely plumbed and have done a test run with freshwater and have no leaks. Currently I have 90 degree elbows with strainer fittings threaded into the two return bulkheads in each back corner. I am debating whether or not to build an overflow box around each of the two returns that I have or to just leave them running with the strainer fittings. The tank will be run as a FOWLR and I have a sump with a EuroReef RS 180 skimmer and a Mag 12 as the return pump. I believe the advantage of having overflow boxes vs. strainer fittings is an increase in the amount of surface water being returned to the sump resulting in increased skimmer efficiency but I am not sure if going to the extra effort of building overflow boxes around my return drains is really necessary for a FOWLR setup. Does anybody have any thoughts or opinions on this?