May not be necessary for either, but I'd rather put the bulkhead fitting above the usual fuel level. I'm sure it's leakproof, but I'd rather give it every chance to succeed. Also looked cleaner with how I routed the fuel lines outside of the tank.
Ran it to the bottom to kill splash. With the built in return line on the sending unit I could hear a sound like someone peeing in a pool from 20+ yards away. Not foaming up the fuel is a plus too.