I could use some suggestions for cutting the 5 inch hole in the side of my Smokey Mountain to accomodate the Cold Smoke Adaptor. There are rack mounts inside the smoker which would make it difficult to use a saber saw to cut the stainless sheet metal(probably 20 gauge at most). I saw that Iceman used a Plasma cutter and I do have a friend with a metal working business that has a plasma cutter but am open to any other ideas.
Before cutting the hole you may want to look at the various adapters that go over the Smokey Mountain vent. You may be able to modify one of those to attach the hose of your cold smoke adapter. If you make you own cold smoke adapter you can use a smaller diameter hose.
Here are a couple of examples for a Smokey Mountain adapter:
Adapter for 18" WSM (https://www.rocksbarbque.com/5cfmAdapters.html)
Adapter for 22" WSM (https://www.rocksbarbque.com/10cfmAdapters.html)
A search may find you other adapters that may work better.