I've for the most part sealed the fire box and main grill (is there a tern for this). I have to add some RTV to the firebox lid and a larger diameter gasket to the front of the hood on the main unit but that I've done is a huge improvement. Using just the charcoal tray as the diffuser/baffle with no modifications other than the gasket and caulk and slices of bread to check the temperature distributions the first to rows of bread by the firebox on the right were about 50% darker, but not burnt, than the rest. The temperature easily hit more than 250 degrees using just the temperature gauge on the hood. This was with one load of charcoal in the better Weber Kettle chimney starter, It also kept above 200 degrees for more than 3 hours. So adjusting the vents should take care of that.
I added the rails and used disposable aluminum roasting pan and cookie sheets as a prototype.
The second picture is the bread as I placed them on the grate the third is flipped over.
The heat distribution is vastly improved but not perfect but I couldn't get the temperature above 200 degrees. I pulled the charcoal tray in the firebox out about an 1" for more air flow and no improvement. I added more charcoal and still nothing. I going to use this both as a smoker and a grill.
My questions are how do I get the heat up more perforation in the baffle? Extend the smoke stack?
To even out the heat I know that going to a heavier gauge metal than disposable aluminum cookie sheets and roasting pan will help. Also going to the larger diameter gasket. Is there anything else to look at before I do that? What gauge for the baffle (I'm trying to do this myself and don't have access to much more than a hack saw type tools)? Aluminum or steel (steel will hold heat loner but aluminum is easier to work)?
Is the heating tray for the firebox worth the money? Also have any of you relocated the warming tray in the main unit higher? Found away to remove and also reinstall it easily? I found that it extra space was handy when I smoked some tasso over Christmas but it will get in the way of a pork butt or turkey.