Allen, thanks for your comments.  I can't really argue that for a large
operation, keeping to one (deep Langstroth) comb size makes the best sense.
 
I recall a few years ago, having for the first time some deeps (new
foundation) which I had put on a number of colonies in July, because I was
out of the smaller supers already.  Well that was a good buckwheat year,
and the bees filled those deeps with beautiful capped combs of strong
buckwheat honey.
 
These I harvested, and began running the combs through a lil' Maxant
3-frame extractor. I was amazed at how FAST i was filling the pails!  (Even
though I had to reverse the frames by hand.)  It was so different from
spinning the smaller combs. The handling factor is an important issue, for
sure.  It was readily apparent just from that exercise.  In fact I then
began scheming to convert to all deeps, since the extracting was so much
more efficient.  Alas, I changed my mind after a few more bouts with
lifting and lugging off the really heavy deep supers.  The distance from
hive to truck can seem like a mile!
 
Now, if you have access to lifting devices, as all serious commercial
ventures do, then it makes even more sense to go with the deeps.  An
obvious advantage is that if and when you need quality brood combs in the
spring, you can select just what you need right away.
 
One commercial guy just north of here (well, at least he was still trying
to be "commercial" last I knew) had lots of deeps for honey supers on his ~
"600" colonies.  Soon after starting in the business he started cutting
them down or junking them in favor of the medium-depth ones.  Somewhere
along the line he was convinced that the deeps were too heavy.  Still, he
was running a couple of old ~45 frame extractors, and I can just imagine
how much honey he could spin in a single day with all deeps.  I guess the
handling costs did not dissuade him from moving to the shallower units.
 
Did you ever wonder if mankind is getting weaker as time goes on?  50-lb.
feed sacks where there used to be 100-lb. ones, etc.  By the way, A deep
super is not nearly as bad if you have cleats to grab onto.  The grip with
recessed-handholds-only makes maneuvering difficult when those babies are
full; wouldn't y'all agree?
 
Best regards,  JWG