Newspaper proportions without the bulk
Eleven by fourteen inches is the middle of MakeMyNewspaper's three tabloid options, and it is the one that reads most obviously as a compromise in the good sense. It is taller than the near square 11 by 12, so it looks like a newspaper rather than a booklet, and it is three inches shorter than the 11 by 17, so it is easier to hold and cheaper to post.
The printable area works out at 10 by 13 inches after the half inch margin on every edge. That is a comfortable page for four or five columns of body text, and it takes a full width photograph across the top without the image needing to be enormous to fill the space.
When the extra height is not worth it
People default to the largest tabloid available on the assumption that more space is better. It often is not. A page with more room than your content needs looks sparse, and filling it with enlarged type or stretched photographs is worse than choosing a smaller page in the first place.
The honest test is the word count. Run your draft through the words to pages estimator at this size and at 11 by 17 and compare. If the taller page saves you no pages at all, it is costing you money and postage for space you are going to have to pad.
The same rules as every MakeMyNewspaper format
Half an inch of white on all four edges, no bleeds, images at 300 DPI, CMYK with black text set to 100 percent K only, and page counts in multiples of four. None of that changes between their formats, which makes moving between sizes straightforward as long as you reset the page dimensions properly rather than scaling artwork.