Each image is different, so it's hard to say which settings will work. Many people use several HDR programs and try their images on each to see, for a particular scene, which one does the best job. I don't think it's a real science, mostly just fiddling with sliders.
It also depends on what look you're going for. Anywhere from natural, where there's hardly a hint of HDR, to surreal.
Looking at your images, I usually only do a set of three, but in this case I think you may need more, particularly to get more exposures which show your shadow detail. I think the result would be smoother if you'd done 5.
I never got the hang of Photomatix, so mainly use Nik HDR Efex as I thought it had more intuitive sliders and better presets to give me a head start, although the de-ghosting isn't always as good.
Any HDR program is going to have a main "strength" or "effect" slider that will raise the shadows and lower the highlights, so that what starts out looking like a "normal" image with deep shadows and light hightlights becomes more compressed to you can see detail in each. This slider basically takes you from natural to surreal. I start with that to get the overall effect right.
There will usually be a details slider that gives you more local contrast so you can see more detail.
If the image is too dark overall, I would raise the exposure, then possibly have to go back to the strength slider.
Then I would make small adjustments with black and white points or contrast. And finally adjust saturation.
Here is what I came up with quickly, using the "Details Enhancer" method of tone mapping (which is the only one I'm able to get any sort of decent result out of).
I boosted the strength to 100, raised saturation to 65. In "more options", I dropped the white point to keep the clouds from blowing out, and raised the black point a bit to raise the contrast of the image. I also brought up the temperature to warm it a bit.
The foreground is still fairly dark. I'm not sure what you were after.
If you haven't seen Trey Ratcliff's tutorial, it's a good place to start to learn about doing these.