bleachandvomit

I have a few questions pertaining to overflow mechanics. Ive decided on a 45g cube with an external overflow, however, I'm uncertain of what's best.

1. Do Durso overflows rely on siphon? I'd like to avoid any kind of suction and go with something that "drains" based off of the return pump's output.

2. I see lots of 6 drain-line complex plumbing mumbo jumbo setups around. Is this necessary? I was planning on just having a 500gph dual 1" overflow setup ...