all of my measurements went out the window. eight gallons to 16.25 pounds (only 3/4 lbs wheat added last twenty minutes) resulted in a concrete block of a mash. thinking 0.039" gap is more than sufficient. I had to dump the whole tun into my kettle and filter it off through the bazooka. I added the sparge to the kettle too, I have no idea how much I lost.
edit: best i can tell I lost about 2.5 gallons. I had an eight gallon mash (should have been seven, ended up way too hot) and a three gallon sparge. I'm now sitting about 8.5 gallons in my kettle.