I have decided on my design for my brick/rock smoker. In the process i thought why not build a reverse flow. My plan is to use a 55 gallon drum laying on it's side and build around it. After reading various posts on rev flow i have a few questions. 1 - What thickness or gauge should the baffle be ? 2 - Is it a good idea to have some holes in the baffle or should it be solid ? 3 - How far below the cooking grate should the baffle be ? 4 - Is it a good idea to install a drain tube and valve to the baffle plate ? The chimney will be a 6" stove pipe with an adjustable damper. Firebox will be 18 x 18 and 24 deep. I'll add some vent pipes to the bottom of the firebox with dampers. Any input would be appreciated.