After reading the "Cherry Smoked Tri-tip" post that Mossy Mo posted I started wondering if I might be able to use my charcoal chimney in my BGE to do the same thing that they did with the Vortex. As it turned out I had a spare charcoal chimney that didn't have a handle yet, and it fit very tightly into the very bottom of my BGE after removing the charcoal grate. So far so good.
I filled up the chimney with used lump and briquets for this test, then decided to fill up my AMNPS tube and put that in the mix as well.
I lit up both at the same time and left the egg wide open bottom and top for about 15 minutes then closed the egg and watched the temp rise on my Maverick. (you can see the probe on the left side) I put the probe as far away from the chimney as I could to see what that temp would look like.
After about 20 minutes I had 160 degrees at grill level and decided to see if I could regulate it to a low and slow cook of 225 so I put the daisy wheel on and shut everything down to the settings I would use for a normal indirect cook at 225. The temp stabilized at 216 using those settings, but the AMNPS went out.
I relit it and decided to see at what temperature I could keep it going and stabilized. With the daisy wheel cracked about 3/16ths of an inch and the bottom damper 3/4's open it stabilized at 320 and there was lots of smoke coming from the AMNPS too.
I moved the probe back to the outside edge of the grill and it restabilized at 330. I think this will work for cooking a tri-tip indirect out on the edge as Mossy Mo did, and finishing it over the chimney to sear it.
I'll check the length of the burn and post when I have the info. It's at 333 right now.