For my GOSM big block I choose two different ways to handle reg/long smokes. For regular smokes i use the original cast iron box with an added handle. For longer smokes i use a coffee can with a handle. The small holes are for air circulation within the can, and the large holes at the top are for exhaust, I have to shim the water pan for clearance. Not much of a new and improved idea, but it works for me. I haven't had to use the coffee can yet, so when I do I'll post the results.