I just think you have to play around with them. In a way, since they compromise between the ease of pencils but the freedom of watercolors, the middle ground is not necessarily the best of both worlds. But in any case, I think I'll try mine again.
You have the Derwent inktense? That's what I used to do this German Shepard IMG_2563.jpg
Some areas you can see lines that look like straight from the pencil, not modified with water. Some areas (background) is like pure watercolor. I had a very wet brush and just brushed it against the pencil to load it with color, so was fully "painting" directly on paper, no pencil lines at all. The face is layers. I would draw a color, moisten a brush to spread and soften this color, sometimes dabbing off excess with a paper towel, then after it dries, add another color. However, it never "sets". If you add water to the finished product, you will get more bleeding. So, must keep finished product dry.
Please forgive me for posting my art on your thead! But I wanted to show an example. I thought this piece came out well, but I have a good half dozen others that are muddy and lifeless looking.