Hi Chris,
It’s probably not the best platform, but it very well may work.
The rotisserie rod, on the standard drum without modifications (we do make custom drums) must be 5/16″ square. The motor RPM, for even roasts, should be at least 6RPM+ and ideally between 25-60RPM
It does look like you can accommodate any drum and the 4LB and 6LB for sure.
Also be aware the oven may need to vent a good deal of smoke, and it will likely smell like coffee at the end. 🙂
-Shane