I find mine fiddly. In the sense that there seems to be a point about which I have to make very small adjustments. I divided the range up into 10 segments, and after I hit second crack, I am adjusting the HG from between position 6.5 and 7. Having said that, it is possible to achieve your desired roast profile - it just might take a bit of getting used to.
I am not sure of other peoples experience with the ozito.