When i had my 75 gallon the tank was not drilled i use to find fish all the time in my overflow box, i just set up a 125 reef ready tank with duel mega overflows, with a 40 gallon ecosystem i just love the tank, waited a long time for it,(money). ;)
Wow it looks a lot bigger, good luck with it, here's a link about saltwater and lighting good reading, hope it helps. http://www.reefcorner.com/reef%20keeping_101.htm.