This seems to work best for me too, with the eye cups all the way down, or at least, just out a little, to avoid smudges from fingers or eyelashes, etc. I love the difference in wide open viewing it presents. Granted, I am not wearing glasses for viewing, probably the same as James. But the view is so different than with the eyecups out farther, as James has noted, that even if I am inconvenienced at having to adjust my viewing technique to make it work, it is worth it for me.
It seems James has found the glare is reduced at times doing this, so it is surely something worthwhile trying if you haven't yet. Thank you for passing that on James!