I don't pretend to know much about binoculars, but my experience has been:

While small sized binoculars are nice to carry, don't underestimate the pleasure of a wide-angle lens. When traveling out west the family had along several small ones and one wide-angle binoc ... and everyone was fighting for the wide-angle one. Lesson learned.

On the same trip we bought 7x or 8x (can't remember) binocs for the kids and 10x binocs for the adults - figuring we'd be able to hold them more steady. We couldn't. The shaking got pretty irritating over time. I think the 8x was good enough. If we need higher magnification maybe a telescope on a tripod would be best brought along.