I would like some advice on about where to put baffle or heat plate and size firebox i need.
Derek, morning..... Do a little reading in the link below.... Gather some ideas on your build... Gather the materials.... that forum will be a great help to get you going... when you have a specific question we are here.... In my signature line are several calculators to help you out also... The calculators can be confusing so don't hesitate to ask questions..... Dave
One more thought on size, Depending on where or if you use a water pan allow for that. I sit mine on the RF plate so I don't take up any usable space on my grates. I have two slide out's. when I do turkey I just remove my top rack and I can cook two pretty big turkeys.
The smoker I was telling you about my son built he also has two racks. The top one you can only load small stuff like sausage, boudin, or a rack of ribs. If he cooks pork shoulder, turkey or anything very tall he removes the top rack. He went ahead and put it in while he was building his smoker just so he would have it. Also put a hinged lid on top of the firebox with grating so he could grill steaks. The pipe he used was a piece of 3/8" x 16" that he had left over from a job. Pipe is pretty heavy. we usually use 1/4" pipe and plate on all the others.
The one picture where the guy is standing beside it, you can really get a good idea of the size. For a couple of people it is really a good size, and doesn't burn much wood or charcoal.