Although not owning an MES, it is a box that collects smoke and or heat in order to smoke food products. Being such, the only reason, in my humble opinion, that some are drilling holes in the top and bottom of their smokers and or increasing the size of the vents, is to create enough draft to operate an
AMNPS within the smoker itself. The downside to this is the more draft the more BTU's needed to cook foods.
Large holes in a smoker or wide open vents are not required unless you want to operate an
AMNPS within it. For example, two of my smokers are Cookshacks, I use a penny to cover the exhaust vents on them when not in use. Needless to say my
AMNPS will not work in them because of the lack of airflow and I'm certainly not going to start drilling holes in either so it will, as they work perfectly the way they were designed.
When hot smoking, the heat generated in the smoker should create enough draft to operate your
AMNPS in the mod. By drilling extra holes in your smoker, unless covered up, this needed draft to operate the AMNPS in your mod would be greatly decreased.
By using a mailbox mod, when cold smoking, added draft through the smoker itself is not needed or desired. Also, when cold smoking a very small fan placed in front of your mod may be needed to keep your AMNPS going and to gently push the smoke to your smoker.
Simply food for thought.
Tom