Bapos,
Like I already said, a pipe burner in the cooking compartment IMHO could only be beneficial, for example, if you were to load 15-20 butts in that were less than 40° that is a lot of cold mass, I would think, from my experience with my
WSM, that the temps would drop dramatically, I don't know I've never used a stick burner, but a couple of cold 15 lbs chucks in my
WSM causes the temps to fall, then again maybe the heat in the smoker walls is enough to counteract the cold mass of meat, ...I'm just 'supposing' here.
As for the pipe burner itself you need to google the "Weld Talk Message Board," after you are there type in "pipe burner" in the search function and then the first choice should be a thread started by "boykjo," he has all the info and a step by step as to how to build a pipe burner. (Sorry I don't know how to post a link)
When I was in the states I worked in a machine shop that built furnaces, furnaces for cremating, burning garbage and foundries, most of the time the orifice was just the end of the pipe, were talking temps of 2800°-3400°, for you fire box igniter you could drill a hole in the side of the firebox and weld in a 1/4" nipple with a brass cap and drill a 1/32" hole in it, if that is too small just enlarge the hole a little bit.
I forgot to say that the pipe burner on the welding forum is for a smoker, there are a couple of them there.
2nd edit: I just dropped in the the welding forum, been a long time, there are a lot more posts, they got Q-view and SWQIB is even there, he built a pipe burner for his smoker!
Gene