Welcome to DiscussCooking. I placed my briquettes down the length of the flame, right beside it. They last a very long time. I haven't even investigated different briquettes for it but I will use some chunks of hickory using a piece of foil as a bowl.
I'm going to switch very soon back to a charcoal grill though - no comparison in flavor!
I hope this helps somewhat! :D
"Count yourself...you ain't so many" - quote from Buck's Daddy