If your looking to add a smoke flavor with a fruit type wood and have it fully cooked but still moist I generally cook at 275 for about an hour depending on the thickness. You want the fish to have a little give when you test it with your finger and obviously you cook on the offset side. Internal temp will be around 145. Cold smoking salmon was recently done by Basher under seafood with great success but, I don't think that's your intention. Just remember that with fish you don't want to overcook or stiffen it to the touch. I like to use Truffle salt on top with black pepper and Garam Marsala for prep, works for me. Good luck