If the tank is brand new and never seen fuel… a 1/8” pipe coupler (threads on the inside made to couple two 1/8” pipe ends together) can be drilled into the tank, positioned 1/2 way and mig welded.
I do this in the shop all the time. If worried about the weld - mix up some JB weld and neatly cover your weld.
We pressure check the tanks after we are done at my shop. That 1/8 will allow a 1/8” male pipe to 1/4” barbed adapter.
Easy piezy.