The only place I have seen slatted racks and follower boards discussed
is in Killion's _Honey_in_the_Comb_ from Dadant Press.  Killion swears by
both, the slatted rack to cut down on drafts into the brood chamber and
to provide room for bees thereby relieving conjestion within the hive,
and the follower board to insulate between brood frames and hive wall
and to provide room to manipulate frames after the follower board is
removed.  Killion calls for a follower boards on each side of the
brood chamber.  I highly recommend _Honey_in_the_Comb_ which contains
many good tips besides producing comb honey.  The section on queen
rearing is top notch and excellent for both small time or commercial
operations.
 
I have never heard of cluster boards, buy hey, two outta three ain't
bad!
 
Aaron Morris - I think, therefore I bee!