Considering sump, help

[cerolost]

I have a 72g bow that I am setting up and originally I was going everything hang on back. Well when looking into the skimmers that would be good their in the 250-350 range when an octopus 150 is only like 180 and is a better skimmer. I do not know much about sumps except the basics. My tank is not drilled so that leaves me with an overflow. I need the most surefire way of not overflowing and flooding method out there. Heck if it is sold in a package for more money I would probably buy it. I anyone has any experience with my tank or can point me in the right direction I'd be happy.