I've been smoking salmon (chinook only) for 20 years. I've developed my "process" over many runs and really like how the product turns out. Here is what I do...
Dry Brine-
2 pound bag of brown sugar
1 cup Johnny's Seasoning Salt
3/4 cup lemon pepper
3/4 cup ground black pepper
I use a sealed container to mix the above items, 3 batches at a time.
I lay out the salmon, previously frozen, into equal sized pieces on paper towels for 1-2 hours. Once the moisture has evaporated off I put a couple of cups of brine in the bottom of a 2.5 gallon kitchen container and start layering the salmon. Flesh to flesh, skin to skin and putting 1/2" of brine between layers. Then leave at room temp for 12 hours. Flip over and place in the fridge for 24-36 hours, flipping the container a couple times a day. Before smoking give the salmon a quick rinse and again layout on paper towel for 1-2 hours. While waiting for the salmon to dry and come up to room temp I preheat the Bradley. Place the salmon on the racks with equal spacing, on the bottom 2 racks I only place the salmon on the door side (the back side of the lower racks gets too hot when the heating element is on), and use the top racks for the thickest pieces. Don't pack too much, your run times will go way up. I prefer to do an extra run rather than stuffing the racks full. 3 hours smoke only, 1 hour at 120 and then 1 hour at 160 to finish the thick pieces. I tend to pull the bellies and tails about half way through the 120 temp. To tell if it is "done" I judge by the firmness and if it is looking dry. I like a moist product. Once finished I let cool for 10-15 mins then vacuum pack, leave in the fridge for 12 hours then into the freezer. I feel sealing the salmon quickly helps seal in the moisture.
Tip- Don't be in a rush to get the salmon into the smoker. Take your time and bring the internal temp up slowly and constantly. Otherwise you'll see a white liquid on top of the pieces which is a protein release from heating too quickly.
Love to hear others feedback.