I bought an empty paint can, used a can opener to remove the bottom.
Then I put it in the middle of the fire ring of my WSM, and poured a
mixture of Royal Oak lump and <gasp> kingsford (I was low on the good
stuff) around the outside, to the top of the ring. Poured a chimney
full of gray coals in the paint can, and pulled the can out with its
convenient handle.

I cooked a 6.5 lb pork shoulder for 9 hours and never had to add
coals. Just knocked the ashes off 2 times and added cherry wood chips
a few times. I had the bottom vents almost all the way closed and it
stayed at 240 degrees F at the grill level all DAY! Hallelujah!

Oh yeah, I almost forgot: the pork was delicious!