I have a Gen. 1 Helix 10 SI and in my opinion, the DI is not very useful at all, as it is using the blended beams of the SI and software interpolation to develop the DI view. The 2d and the SI work great and are very useful, the DI views, hardly worth having.
When I view the images that members post here of their true DI returns, I'm amazed at how good they are compared to what I've seen.
I don't hover over spots continuously, like brushpiles or rock ledges, so the DI really is not applicable to my fishing methods. Like you, I have played with it quite a bit but never was satisfied with what I saw.
Yes, I was talking to myself; sometimes even I have to ask for expert advice.