If cooking with a clay pot base in my pan instead of water, my objective is not only to catch drippings in the foil, but to keep them from smoking before I foil the meat.
Anyway, I'll make sure the depression of foil where the drippings accumulate doesn't touch the clay pot base underneath. I did a little double butt cook Saturday in my new 22.5" at around 250* and didn't notice drippings burning smell until AFTER foiling each butt at IT*'s of almost 170*.