What is a way to figure the pads from a datasheet where the part diagram leaves out dimensions?
If it &quot;actually matters&quot;, contact the manufacturer and ask for mechanical drawings.
If it doesn't matter that much, do what you're doing (which is, roughly, what I would do for hobbyist applications), or as an alternative, import the footprint as an image directly into Eagle. I haven't tried this myself but there are many tutorials.