Since you used the technique that I posted... I've been racking my brain trying to figure out why it didn't work for you. Your process sounds just right, except for using chunks rather than chips as everyone else has already suggested. I always use chips for fish. And since the fish isn't in the smoker for very long, you can throw a few extra chips in there without worrying about it getting over-smoked. Also, you might notice more smoke flavor, or a different more mellow smoke flavor if you wrap and refrigerate for a couple days.
As far as the thickness, you want the thickest salmon you can find. I buy whole skinless filets from Costco. I cut the filets into about 4 inch wide sections, using the thickest part of the filet toward the head. The other 1/3 toward the tail gets used for something else, like sous vide, or salmon burgers. You can smoke the thinner tail part too if you want, it just cooks really fast and is prone to drying out. Also, certain species of salmon have more flavor than others. Try to avoid Chum/Keta. I has very little flavor, and I've heard Alaskans won't even eat it, they feed it to their dogs or use it for bait. I don't think Coho is all that great either. Probably what Costco sells is farm-raised Atlantic salmon, which I know you are supposed to avoid for various reasons, but it is very high in fat, which means flavor and moistness, so that's what I buy for smoking. And the price is right.
Thanks for the additional feedback, Kari. I'm going to Costco next week to get pork and fish.