It’s incredibly hard to create facing-page aligned texts in a way that doesn’t periodically lead to masses of wasted space on one or another page. The only exception I’ve seen in the age of digital typography is the Clay Sanskrit Library—and yet, though I know that their volumes were all typeset using XeLaTeX (in Adobe Garamond!), I have never been able to figure out how they got the linespacing just right, so that there’s never any wasted space at the bottom of the Sanskrit pages!
Also, I once came across a (commercial) piece of software that allows you to produce Loeb- (and Clay-) like parallel texts without any wasted space, by including synchronised markers in each text, which is amazing, and the perfect solution to this problem—but I cannot for the life of me remember what this software was called (only that it was marketed to classicists), and I’m not even sure if it would run on modern computers (I came across it in 2008 or so).