If you really want a slatted rack, just screen the bottom and prop up the lid to make a top engrance and save your money and don't buy the SBB.
I've gone to bottomless hives, 10 inches off the ground and use a slatted rack w/o screen, if I were to use screen on the racks it would be 1/2 inch. The rack creates a dead air space thats serves as insulation, the slats themselves keeps out most predetors, and without the screens to catch mites, wax scraps, etc, everything falls to the ground where it is hauled off by ants. For some reason, with a bottomless hive, the ants stay out of the hive. I guess because they have access to what they want from the hive being dropped in front of them. I've attached rails on which to slide mite boards, if needed, or to use as entrance reducers.