Remark - the only concern I would have with putting the turkey on the ash pan is that with the curve side facing down there is nothing to trap the heat & smoke under the pan and force it to travel the length of the smoker. So even if you baffle the firebox to force the heat down it will imediatly rise once past the baffle - but never having tried that method myself I suggest you try it and keep a close eye on your therms.
I personally used a hose clamp to attach my dryer vent tubing to the inside of the stack, then at the grate level I drilled a 1/4" hole and put a 1/4-20 bolt through and used a wing nut and washer on the inside to secure it. (Probably overkill, but... never know)
If you use some sort of silicon or adheasive to hold the rope gasket make super sure you clean the area that it will be bonding to. Any grease or film will make it so the gasket does not stick. I have seen some people use a combo of silicon and rivets. Silicon makes a nice seal, rivits hold it in place real well.
For therms your best bet is to get a digital with probes for meat and chamber. But if not (or if cheap like me
), I have two at grate level - one on the left and one on the right. They work great and are easy to install.
Definately get a basket. The shaker basket from Lowe's seems like the easiest way to go. If you don't have one you will be spending a lot of time tending the fire.
All in all these are great units for the non-competition users. They hold a lot of food for that big family dinner or the block party, and once set up don't take a ton of babysitting. Just don't tell my wife that.... I have her convinced I have to spend 6-8 hrs. "tending" the smoker (with a beer).