It sounds like your dialing in your technique. Slow and cold is the way to go for fish. On your next batch, air dry your fish for 24 hours until a pellicle forms on the surface.
(Before
cured foods are smoked, they should be allowed to air-dry long enough to form a tacky skin, known as a pellicle. The pellicle plays a key role in producing excellent smoked items. It acts as a kind of protective barrier for the food, and also plays an important role in capturing the smoke’s flavor and color.
Most foods can be properly dried by placing them on racks or by hanging them on hooks or sticks. It is important that air be able to flow around all sides. They should be air-dried uncovered, in the refrigerator or a cool room. To encourage pellicle formation, you can place the foods so that a fan blows air over them. The exterior of the item must be sufficiently dry if the smoke is to adhere)
Waiting for this to form, you'll notice the meat become translucent and the pellicle will form on the surface, then throw in the smoker. This will make a world of difference in your end product.