Where do I Drill My Bung-Hole?

Don't drill anything. Get a fuel sender with a 1/4" return on it.
Yeah, I suppose This would be the Fastest Way to get er done. It's Easy enough to find a 3/8" out 1/4" in pickup
and the Sock fell off my crappy pickup in the tank anyway.
Thanks Triple R!
and I think I'll take the advise of 67Dart273 and use my existing 5/16" line for the Return and Run a New 3/8" Line to the Pump...

pickup.jpg