A little update:
I decided to cut the bottom of the drum out as the original drilled out diffuser/bottom was too close to the coals and restricted heat flow as I was not able to reach temps above 300F, with the vents fully open. Coals were also not burning efficiently. I tried both, using the Smokey Joe Silver and the Gold....didn't matter.
I will run this meat hanger smoker body with no diffuser.
Here's a shot of the 16 gallon drum with a single meat hanger rod and a cut out drum bottom and Smokey Joe bottom: