>>A beekeeper who is very big top entrances propagandist here 
suggests top entrances to be 3.5cm diameter.

I don't like drilling holes in my deeps.  I place a ~1/4" (0.65 cm) 
dia stick under the top insulating newspaper.  The stick extends from 
the inner cover hole to the edge of the inner cover.  I find that the 
moist air flows out of the hive well.  I don't see mildew or mold 
inside the hive.  The newspaper absorbs a little moisture along the 
stick but this does not compromise its insulating value.

I do have drilled holes in some of my medium honey supers to help 
provide an airflow in the summer months.

>>I understand that slatted bottoms have some other adventages but I 
didn't unify my hives, it is maybe not too much serious of me.

I've read/heard slatted racks reduce swarming but I have not seen any 
comparisons with regular colonies.

Waldemar

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