I would think that by now you could open up the entrance more. I leave mine wide open except in winter.
If you have an active, healthy hive and haven't given them too much space/to many frames to cover, wax moths shouldn't be a problem. If you give the girls more frames than they can cover, then wax moths can take hold, but that is more likely in old frames where brood had been previously than new foundation.
I have never had any problem setting the telescoping cover back, or even offsetting supers when temps get real high, as they do here in Oklahoma, in order to increase ventilation. I also use slatted racks on all my hives as it gives just that little extra space inside the hive for the girls to hang out and not beard on the outsdie.
Also, are you using a screened bottom board?