Overflows

What is the best overflow for a 75g tank?

both actually, I am doing a hob as my tank is undrilled. Upon reading up on overflows I get the impression that these will fail at sometime and create a flood. I am now leary of doing a hob overflow for that reason. I had originally thought of doing somthing of 600gph with twin 1" drains into th sump with about a 30g sump. The return would be a 1" with a t back to the sump and a gate valve.....I am not sure what size pump I would need but I was thinking of a mag7?