I don't have a D model (I have a #1). So when I make cold-smoked salmon lox, I use an on/off procedure with the knob. I also use the cold smoke plate and a pan of ice. The Big-Kahuna probably works better, so you should stick with that. I usually cure my salmon for lox a lot longer than I cure my salmon for hot smoking. I also put a bit of Prague Powder #1 in the lox cure.
If you are not liking the smoke flavor, I would assume it has something to do with your wood. The Big Kahuna is going to use a different style of wood than what you were using on your homemade smoker. Also, what wood species did you use on your old smoker, and what are you using with the Big Kahuna? If the smoke is too strong, maybe try a different wood with a milder flavor, like maple, cherry, apple or other fruit woods. Sounds like you are already working on the other two variables, amount of smoke and time.
I usually wrap and refrigerate my cold-smoked salmon for at least a couple days before slicing it. It helps mellow the surface smoke. As far as texture, that could be a number of things. You didn't mention how the texture is different. Maybe your old smoker slightly cooked it? Or maybe it is just where you sourced your salmon? Farm-raised salmon usually works best for me for cold-smoking. Unless you can get some nice fatty wild Alaska King Salmon, but I can't justify the price.