Good Morning! I am new to this forum, but have been cooking for about a decade now; parties ranging from 10-150 people. I'm currently working on a 500 gal propane tank, reverse flow smoker. I used feldon's calculator, and based upon it's calculations, I'm requiring a 6" exhaust at 66". Given this is a trailer rig, an exhaust that tall is not possible or practical. I'm inclined to cut it in 1/2 and run dual 6" exhausts at 33". This seems to fit within the "rule of thumb" parameters from what I've seen, and will of course look pretty cool. My question is; early this morning when I should have been sleeping, it dawned on me that two 6" stacks might be the same as one 12" stack. Again, reaching back to Feldon's, a 12" stack would be only 16" long, which seems like it will cause an extremely lazy draw. I want to avoid this since the reverse flow will already slow things down. Unfortunately I couldn't find much, or any, information about people running dual exhausts and it's effect on length and diameter. Can someone point me in the right direction please? PS- i will post pictures this evening.