I did the flange and my metal working skills are Zee-Ro. I c-clamped the aluminum strip to the outside of the drum, bending and clamping along the circumference of the drum, then trimmed the excess aluminum and squeezed/clamped the flange to the inside of the barrel. Drilled and bolted the flange in and ran a bead of hi-temp silicon around the lip.
I do a tinfoil gasket around the lip of the flange as well. Weber lid fits fine now.
1 x UDS, 2 x 22.5" Weber kettle, 1 x COS(for storage), 1 x Kingsford SJS knockoff, 1 x ailing 2 burner gasser.