I made an overflow box during the last week, did the bending by using a butane torch to heat the acrylic and bending it over an edge. I did manage to kill my Dremel in the process, just managed to finish cutting the comb, glad it has a 5 year warranty.
Your tank looks like it's coming along nicely, I'm a little jealous of the size, I'm only doing a 110L saltwater tank with a 60L sump.