After several attempts (see Curing trout for cold smoking) at cold smoking trout, I have at last come up with my preferred approach. The good news is that the cheese is almost as good as the trout so I make time to do that as well.
Having perfected my technique for cold smoking I now include plenty of cheese each time I put the smoker on. I use normal Cheddar and have also been successful with 30% reduced fat hard cheese as well.
I have tried a variety of wood types for the sawdust and favourites include Maple, Cherry and Apple. Sawdust can be purchased easily online and many suppliers do a variety pack so easy to try a few and decide on the one you prefer.
I use this company for my sawdust: Hot Smoked
I have played around with timings but have settled on 10 hours for trout fillets and around 2.5 hours for the cheese. I regularly check that the smoker is still going as I have had it when it had stopped burning and had to be re-started part way through.
My smoker has a large door that I keep closed during the smoke and a smaller panel at the bottom to check the burn.
The final job after the smoke is to slice the fillets and I use a wide bladed knife for this, cutting sideways to get a thin slice. I arrange the slices on a plastic plate, put in a freezer bag and freeze until needed.