Your dark prints are likely due to your monitor being too bright. I had the same issue. Like tolusina said, calibrate your monitor and do it at about 50% brightness level. When you edit or print, remember to set the brightness at 50% (or whatever level you calibrated your monitor on) so you get a more accurate representation of what your print will look like. Also, remember that the monitor is projecting light from behind and through a screen, while a print is relying essentially on reflected ambient light. Those differences in the simple physics of how you view the images will result in differences in how the image is portrayed.Thank you for the great advice TG...
Here's a good resource describing the problem and some solutions:
Regarding your question on art paper, I've been using Red River paper for a couple months. Great stuff, recommended! They have a list of recommended papers for the Pro-1. The fine art papers are at the bottom of the page.
As for the ink levels, it's probably a plot to get you to buy more ink earlier.