bnew, Morning. Seem you have the makings of a new smoker .... I suggest you read about the smokers that have been built here already. There are many....many ideas about shelves, tuning plates, fire boxes, slilde in and out accessories, drains, and more. Find a design you like, extras you like, and will all that fit your skill level and equipment you have at your disposal.
Building a smoker is quite an undertaking and many hours of engineering to obtain what you desire in a final outcome is important. You do not want to build it twice.
There really are some "rocket science" smokers folks have built, listed here. They are amazing, impressive, jaw dropping, too pretty to use, etc. You can tell who put many hours of thought and engineering into their projects.
That being said, Welcome to the best smoking site on the web. Please fill out your profile with a little more info to introduce yourself to the great folks here. The folks that run this place do an outstanding job and everyone is ready to give great advice.