I have been reading / lurking here for quite a while. I am building a 250 gallon, reverse flow trailer smoker. I see all of the intimidating mathematical equations for figuring out the fire box size and the size of the holes and it makes me worry. I just did what looked right to me. I got a 250 gallon propane from a local gas company here in Jacksonville, FL for $35. I bought an old jon boat trailer from a guy at work (i need new wheels and springs). I got the scrap metal for the fire box for free from work, I work at a shipyard. I have been working on it for a while. I hit it in spurts, when I have free time. I am gathering my pics and will post them soon. I have some galvanized sheet metal to put in the bottom, for the smoke chamber. should I remove the galvanization befor I use them?