Try this dry brine recipe:
Box of Brown sugar(16oz)
1/2 cup non-iodized salt
2 TBLS Black pepper
1 TBLS Dry Mustard
1 TBLS Onion salt
1 TBLS Celery salt
1 TBLS Garlic salt
....add more sugar as desired
NO LIQUID added
Mix all ingredients and put into two 2 gallon plastic bags evenly for one 15lb or so salmon.
I have had best luck cutting fish in 1" steaks to smoke so all is same thickness.
Cure for up to 20 hours in fridge but turning bags every so often.
The Dry brine will turn to liquid within hours and will need to be turned every so often until it is ready to smoke. I have found the best AVG time is 16-18 hrs. It depends on the thickness of the fillets or steaks. If the fillets are thinner than 1" then cure less. Use a Little or Big Chief to smoker until done. I use Alder chips but you may use any of the other flavor of chips.
This recipe was posted on another board several months ago. I've cut the brine time to less then 8-12 hours and have noticed little differance. I'd say of all the spices in this that pepper is the most important. I've substituted curry and used crushed peppers to get fish with kick. Excellent with a beer!