One beekeeper that I know uses a little different idea
for making his splits.  I have never tried this as I
have never tried for big increases but it sounds like
a good idea and he is quite happy with his results.
He starts with a strong hive and completely consumes
it to make up nucs.  Like 4 5-frame nucs from one hive.
The old queen can either be killed or used in one of the
nucs.  He feeds the nucs and puts them into regular hive
bodies a few weeks later.  These nucs can build up fast
and the hives can produce a surplus provided they are
started early enough.  In this area it is about the first
week of april.  You will need at least 2 frames of brood
per nuc.  A quite a few beekeepers in this area make their
increase into nuc boxes instead of hive bodies.  I have
done it both ways and would vote for the nucs but it is
more work as they have to be monitored and moved into hive
bodies usually within a few weeks.
 
Vic Kroenke
Kansas  USA