Solar , I have a NewBraunsfeld Red River model I reversed quite a while back and it does a great job. i used a SS plate I foud and trimmed and shaped it to fit the Smoke chamber , I also incorporated in a drain for the grease and moisture.
Here is a shot of it :
It's the small one to the left...Smokes good and has lasted 20 years so far
The big girl is a tejas2040CC , and a dream to cook on