21.5 kettle extender?

[effinUker]

If i had the rotisserie accessory i would probably use it. But i want to use it for smoking and it looks like smoke would leak like a sieve.

By the time the smoke leaks, it don't matter. It's leaking either at or past the meat, so it's just exhaust. I don't have any trouble keeping a temp with smoke coming out the assorted orifices.