I wouldn't define a printer page size of 17x7 or 7x17. That doesn't make sense to me. On a 24" printer I might have a page size of 8 x 24 to accommodate this image. Are you using roll paper or sheets?
Printing from Photoshop is frustrating at best. Maddening most of the time.
Give the trial version of Qimage a try. It might make more sense to you. Take advantage of the learn by example tutorial.
There are those who will complain about the Qimage UI. They're generally the ones who've forgotten the years they've spent rationalizing the Photoshop UI.
I have been printing from Qimage for years now. It uses color management and has free lifetime upgrades, and does interpolation and profile/size/resolution based output sharpening on the fly, so that you never have to uprezz and save humungous sized files if you don't want to. Qimage also lets me bypass the printer's fetish of having unequal margins on the page. While I have a 24" Z3100 for larger prints, I have found it easy and less expensive than my smaller printer in terms of ink and paper costs to make smaller prints as well Here is what I do:
1) In the Z3100 driver, I set up some custom sizes: 24"x 8.5" and 24"x17" for example, with the printer set to eliminate white space above and below the print. I use the first size to print 2 8.5x11's in landscape orientation, or 2 11x17's in portrait orientation, per page. I then line them up on my mat cutter and cut them to size, easily.
2) In Qimage, the selected printer page size comes up in the preview, for example, 24x17. I have custom sizes in Qimage for 11x17, 8.5x11, etc. If I am doing 11x17's I select that size, the profile and rendering intent, the interpolation if any, and the output sharpening, as well as other parameters. I use Optimum or Optimum Spaced, and my images come up 2 to a page, and can be seen in the preview.
In addition, Qimage is directed by my choice to the folder I use for images I might want to print, with the sort-order set for the most recently worked on images to be the first thumbnails in the window. There is never any question of which images I want to print.
Qimage also has a very accurate softproof for last minute checking of color, and many other features that make it my choice over Photoshop for printing. The layout choices, I think, not only beat Photoshop's in terms of ease of use, but are equal to a good RIP.
In my years of shooting, processing and printing my images there are only a few programs that I consider indispensable. Photoshop is one, and Qimage is another.
Disclaimer: I do not work for DDISoftware, nor am I related to any of their employees.