Terminator

My tank was not as pictured either.

I used a two line system with a Slimline Ultra Fueler:
One line goes from the clunk to the Ultra Fueler then to the Carb. The second line goes from the top of the tank (bend in tubing) to the muffler pressure tap.
Both lines came thru the stopper.

The tank I received had a nipple at the bottom of the tank. If you use a three line system ( one for fueling/defueling) this nipple could be used. Mine was not open and would need to be punched out if used.

The screw hole you referred to I believe is the hole used to keep the stopper in. A screw should be supplied for this.

I went into detail not knowing your level of building experience.

There are several ways to setup a fuel system ... fuel dots, Fill Valves, etc..

I stay away from spring loaded fuel valves. I was advised by club members that have used them .... vibrations cause the spring to fail ( then leak), and then flame-outs have been encountered on takeoff etc..

Hope this helps ... others may have more ideas/suggestions for you.