I've tried this on the last three smokes,and I think it really helps, really helps when its cold outside.
I used 3 bricks placed on an extra rack on the bottom shelf.
I preheat to 350 and place on bottom rack when i put the meat in this helps the obs get to operating temp alot quicker.
Before bricks when ever I opened the door it would take atleast 30 minutes for the obs to recover. The heat stored in the bricks really cuts down on recovery time .
Also with the extra heat holding mass of the bricks I notice my obs and pid cycling a lot less.
I usually keep one or two foil-wrapped bricks handy for this purpose. I put one under the bisquette runway and one on the V-tray if it will fit.
Using the whatever size foil pan that fills the bottom of the bradley filled with hot water also works well and has the capacity to not require changing on a long smoke. Either way it is a great tip. :)
I use old time flat irons in mine wrapped in foil. Also works well.
I have been useing feild stone stacked in around my water bowl, it seems to work great for me.
It just occurred to me to perhaps use an old cast iron frying pan as a water bowl. It would have higher capacity for spent pucks, and make a great heat-retainer. It could be a problem to empty. Hot and heavy are good combos for some things, but not necessarily cooking....