Thanks for your patience with this one. I have moved to London and things have been a bit hectic for me personally. Your images have improved quite dramatically since the beginning.
Given the assignment here is to try to achieve a wide tonal range and that it should slant toward the darker end of the spectrum I can tell you that you've done well.
Now I always want you to try to achieve the best image you can when you're out shooting. This is critical. Don't rely on post processing tools unless you need to! Once you're sure you've done the best you can, in camera, then you can always enhance and fix your images in post processing software after the fact. In this case one thing you can do to improve the tonality of your image in photoshop is to look at the equalize adjustment.
If I remember correctly it's under Image > Adjustments > Equalize. It basically remaps the bright pixels in the frame to true white and the darkest pixels to true black. More importantly the equalize adjustment also spreads out the midtones over the tonal range effectively creating an image with more tonal range.
But remember, get the best possible image you can IN CAMERA! I can't emphasize this enough.
The reason is that if you start with garbage you will just end up with slightly polished garbage after photoshop!
Nice work here. I like that you have developed a style and a theme around your work as well.