Put the shim on top of the first super and under the second super, entrance
hole down.
One for each super is too many and not necessary.
I use one over the 1st super, the next one over the 3rd super, and an upper
entrance slot in the inner cover over the 5th super.
Imirie Shims are ONLY USED when supers are in place - NO OTHER TIME and NEVER
BELOW THE QUEEN EXCLUDER.
I have no idea how many people use them. Steve Forest of Brushy Mountain
says he sells a tremendous number of them, what ever that means.
I use 2 per colony and I had 135 colonies until I had disabling strokes.
Hope I have helped.
George Imirie