Adapter Plate part number for BTSG1

[ddtdustin]

Does anyone have the info on the adapter plate for the SG?  I have a OBS SG and would like to use it on a refrigerator/smoker build.
Does anyone have any comments on watt requirements/loading for a refrigerator/smoker build.   The internal dimension are 24x15x34 (7ft3).
I know some really nice post on here are 3000w at 220V for ~20ft3 (or roughly 150w/ft3). 
I have also found where they have calculated required wattage and meat loading.  I am not sure how this is done.
Thanks for everything
DDT