Flange mod! I do this for the open drums with lids, it allows me to use both lids. But one thing I have noticed using a Weber lid without the flange on closed drums is that they leak greasy condensation down the sides of the drums. With the flange it does not.
Closed drum with top cut out and kettle flange
Open top drum with flange in place
Flange removed and drum lid in place
I use a cut off tool on the kettle