I have been tinkering and building supers today and am considering using
the scraps for an anti varroa floor of my own.
   On a regular bottom board I plan to smear with petroleum jelly I will place
a piece of hardware cloth with 1/8" openings in the mesh. On top of the mesh
will go a frame of 3/4" stock on three sides so that the entrance to the
hivebody is above the mesh and debris and mites are free to fall to the
grease.
Another piece of 3/4" stock will seal up the original opening in the bottom
board.
I am also considering wiping the hardware cloth with mineral oil and if this
shows results I will arrange the next ones with the hardware cloth let into a
groove so that it can be slid out like a drawer to recoat.
I should imagine an arrangement like this will confound hive beetles as well.