| You may not be able to completely copy the set up on your 50 gallon. Chances are on a 150 gallon tank, the bottom will be tempered glass that cannot be drilled! Depending on the tank, the sides may also be tempered. If not, you might be able to build a horizontal overflow chamber that drains out the back. Most people make their overflows from clear or black acrylic that they route out the teeth in.
I would also consider the possible issues with a 150 tall. It will require very strong lighting and long arms to reach the bottom of such a deep tank, which is probably why they aren't popular reef tanks, Just some things for you to think about. | 
