Hey Nate, I use an old aluminum non-stick skillet wrapped in foil for my diffuser. I had an old scratched one scratched to hell that was given to me. I just cut the rivets holding on the handle, rather than drilling them out, so that if the foil leaks, the pan wont. I've found that's all I need. It is light enough to hit 275-300 for chicken but still allows me to run at 225 when needed.
Damn, I need to post pics. A recent move has kept me preoccupied.