Hey mate, I've done tons of ocean run rainbows & the best way I have found to do them is to brine them in a 50/50 mix of salt & caster sugar, you heat half the water on the stove to dissolve as much of the mix as possible, then add the other half of the water to chill it back down. Add the fillets, the refrigerate overnight. When you take them out of the water give them a rinse & pat them dry with a paper towel & leave them on a tray to for an hour or so to get a nice pelicle(sticky to touch) this will help the smoke stick to the fillets.
Once you have brined them you paint them with honey(you can sprinkle with brown sugar but I find honey is better, bit more of a fruity sweetness).
Now, you have two choices from here, you can hot smoke them for about 4-6hrs till you get an internal temp of 57C(135F) or you can BBQ smoke them at 135C(275F) till you get the same internal temp, about 30-60mins. Both ways turn out amazballs but the BBQ is a bit more like a cooked piece of fish & great as a meal, whereas the hot smoke is, well it's like smoked fish & better for an entree with biscuits & sour cream/crème fraîche or a snack with a nice beer.
You can also dry brine the fillets, but this gives a more salty taste & is more suited to mackerel or barramundi. Let me know if you want to try the dry brine & I will post the rub recipe.
)
and amazballs ? 
