Ok, so at the expense of looking like i don't know what i'm talking about (cuz i'm still trying to figure this out LOL)
and as i tell the tech's that work for me "the only stupid question is a question that isn't asked" LOL.
the gap bbally is refering to is the gap at the end of the plate. i too still do not completely understand this, i wish i could wrap my brain around it. i have a strong mechanical background from working on food equipment and refrigeration equipment, but the engineering side eludes me,LOL. the "dead volume thing" as far as i can understand (and i am getting this from context so i could be wrong) is referring to the volume of the cooking chamber compared to the volume of air being exchanged (i think) so if the gap is too big, it allows the cook chamber to fill with new products of combustion faster than it can exhaust (? is this right?) so the products of combustion will then cool off before they are exhausted out the flue and thus soot up.
i am assuming that "temperature gradient" is refering to heat loss, or temp drop of the products of combustion?
so i am still confused a little as to the proper gap.
i have heard and also reasoned out with myself that the proper gap is equal to either the flue volume or the area of the inside diameter, i'm unsure which.
it is equal to the area of the space under the baffle plate.
i feel it is the first statement but since it is easier for me to add to the length of my baffle plate in my smoker i'm building i have decided to go with the second idea. all i will need to do is add a piece of flat steel above and horizontal to the upright that blocks the end of the plate and it will make the gap closer.
now as far as knowing how to balance the intake and flue dampers, i don't know what to watch for that will tell me which one to open or close. any help or additional info is extremely appreciated! once i figure all this out for myself it will be easier for me to help others with these questions and give something back to this wonderful community!