I agree I own a pitbull. I have him with two other dogs all which get along fine. He's one of the nicest dogs I've owned I had a chihuahua that I was way more scared Of attacking me. To give you an example while the pit bull is eating I can reach down into his bowl with no worries no aggression...
The overflow is basically a PVC elbow in the tank. I have a 30g fuge under the tank and a 36"x16"x20" sump on the side. Skimmer I'm using is an MSX 200. And for lights I have a 250w radium in a lumenmax elite reflector. I don't think 400w is too much just gotta be careful when acclimating corals...
I just finished goin from a 30g to a 60 cube but I set the tank up with rock that I had curing for almost a year. Then left the tank running for 1 month and transferred everything over a weekend. I had a small diatom bloom and all is doin well now.