Jeff - One problem I have encountered with high volume waterfowl shooting with a choke tube that is not a snug fit is. The choke will unscrew on it's own, and you must pay very good attention, as I have seen guys shoot the choke tube out, when things get hot and heavy, especially for Snow geese. While the gun is empty and the barrel warm always check the choke tube
I use a very small amount of Clenzoil on my choke tubes, but even dry, the IC in my M1 likes to loosen itself after many shots. It is the only choke tube I have that does that, so I check it prior to reloading.
I am also new to the In Line muzzleloader use for deer hunting, after using a Flintlock every year since PA opened their season. So much for a In Line being primitive...
I would question the use of any type of "grease". Because the muzzle of shotguns get dirty with mud, dirt, sand, etc. and the grit in the grease would foul the threads which are much thinner than a breech plug.
Just my own experience and 2 cent worth.