Jack,
 
You Wrote:
 
>  Why use entrance reducers?
>  They R extra cost and extra work.
>  In 35 years of consecutive b-keeping,
>  I have NEVER used any.
>  I run the shallow (shallow) side of
>  the bottom board up (up) year round,
>  NEVER the deep side, despite what
>  the books and soit-disant experts
>  say about the necessity of "adequate
>  ventilation." Suum cuique.
 
Not to pick nits, but I believe it would be more accurate to say that
you ALWAYS use reducers. Some of us only use them seasonally.
 
With just 3 hive I don't mind putting some 4 sq/inch hardware cloth in
the entrance. If I didn't the mice living under the hives would probably
invite their in-laws to live "upstairs". That would violate one of our many
zoning ordinances.
 
If I had many hives I think I'd go with your aproach, though.
 
Kevin