first let me say welcome!
this is my two cents
First figure out a few things before choosing a smoker:
How many people do you wish to feed with this machine?
Do you have access to wood or will you use pallets?
owned a restaurant which is great! but remember that your restaurant never moved around, so plan to get a good set up so that you can operate comfortably without having to worry about issues like rain.
Weather in your area? do you need a rig that is super insulated? or maybe you need a permanent roof over the whole thing if it rain a lots in you area?
proper washing area is an absolute must if you will be cooking for general public.
make a list of all those things then start shopping for your BBQ.
hope this help.
cheers,
Martin