This thread should be pinned at the top!
For cold smoke, I always take the skin off as I want to make sure the fish is cured. For hot smoke I leave the skin on; keeps the texture of the fish and the omega3 business in there. All my brines are dry mix of 3/1 brown or regular sugar to Costco's ground pink salt. I also add freshly ground black pepper, paprika, bay leaves etc, whatever I can find.
I am still a newbie and yet to learn the non-dry brines...
Alternative to 3/1 sugar/salt, I can do 2/1 and a 2 spoons of maple syrup per ziplock.
I also cold smoke boneless turkey breasts (as a last resort, chicken is ok too but turkey is strongly preferred) and they are a blast too. Throw them in a 3:1 mixture of brown sugar vs salt for 3-4 days in a ziplock and then cold smoke. It is called "basturma" in Russian and many other languages. Some also call it "pastirma". Not to confuse with pastrami, it is a different thing.
On the picture below, cold smoked turkey/chicken breasts on the bottom, rainbow on the left, coho on the right.
I am not sorry if this makes you run to the fridge