N8Man ... I'm using a flat lid on my open top UDS smoker at this time and have a closed end drum to use as an extended lid instead of a Weber lid. I'm intrested on how the two mate and if they will seal fairly well. I'm not planning to modify the UDS, just add an extended lid.
Small Charbroiller, 40 year old barrel pit, UDS, 97 Weber Performer, Brinkman gas grill.