In answer to your orientation question...C3D is orienting in a "readable" and parallel to the contour line. You may change the orientation to whatever you want in the style settings. I am not familiar with an orientation from lowest to highest...generally I see contour labels online and parallel to the line being identified.
On your second question...I am not sure what settings you have in the style that are masking the contour... Might a linetype be creating the gaps? Or some other setting?
Lastly, it looks like you need to click on the apply or is it the arrow pointing downward to send the new number of ranges to the panel below?