I have an alum tank. When filling, I set the nozzle all the way and lock the filler at the slowest rate. It gets full w/o belching anything up. The fuel vent or drain back hose allows easy filling.
For leak, the first thing I'd check is the filler hose clamp at the tank. If the clamps are already tight, pull the filler hose off, and inspect the sealing surface. Maybe there's some casting flash or debris preventing a complete seal.
The fuel sender on my car was pretty bad. No matter how I adjusted it, it would never work well. I replaced with a Holley universal sending unit, and now it works well.
Fuel Level Sender