I need to have a built in overflow on a 120 gallon acrylic tank. I need have the overlow drilled for a bulkhead and need a suggestion on the size to go with. I will be running a panworl 50PXX return (about 600gph). I am leaning towards a single 1.25" bulkhead or dual 1" bulkheads. I am open to all suggestions, I need to have this drilled tomorrow on pickup.