Following on the comments of Mr. T and TN Q, you first need to focus on your desired end result and how you're going to serve the fish. Is it going to be served upon finish as an entree, or is it going to be chilled and served later as a snack, appetizer, or as a component in a spread. Then you adapt your preparation and cooking process accordingly.
If I'm serving the salmon, or most other fish< at finish as an entree, I cook it, smoker or otherwise, to an IT of 120°-125°. I pull and foil it for a few brief minutes, then serve. Some would consider this underdone, but I think it's perfect. As TN Q said, the flesh is creamy with little if any flaking. I once had a conversation with a chef at the bar of his restaurant in NYC, which many critics consider the finest seafood restaurant in the country. He commented that any cooked fish that flakes easily is very overcooked, and I agree with that. He also said that the best way to test the temperature of a properly cooked fish was to insert a metal skewer into the thickest part for a few seconds, then press the skewer to your wrist or lips. If it's just warm, not cool or hot, it's done. I've tried that several times and it matches up with the temps I mentioned.
On the flip side, if I'm doing the fish to store and serve at a later time in whatever manner, I follow Mr. T's process and take the IT to 145°, pull and wrap in foil for 30-60 minutes, then refrigerate for later use.
When it comes to curing or brining, if I'm cooking the fish to serve at finish, other than to impart additional flavors, I don't see why this needs to be done at all. If I choose to do it, I'm just looking for a specific flavor profile and am not concerned about specific salinity levels. Obviously, it's a different story if your preparing the fish for preservation and later use.
When it comes to curing or brining, my preference for a long time was a dry cure. However, as Mr. T said, it's hard to get consistent results unless you have your process down pat. These days, more often than not, I use a wet cure, or brine. In my experience, it reduces the curing time by about 50%. Turning the salt into liquid is effective because it touches 100% of the food's surface in a uniform manner. Salt has to dissolve before it can work its magic, so using dry salt is slower, and less controlled, than using brine.