Architecture that facilitates validation of a data mapping of data from a data source to a data target. The kit includes a base having an upwardly-opening recess; containment blocks, each with a central vertical opening, that are stacked atop the base and extend the recess upward; supporting blocks that are received within the recess for supporting the furniture leg; and a plurality of shim blocks of differing sizes. The subtraction circuit outputs a differential voltage between output voltages of a photodetector element and a photodetector element. In addition, the method modifies the transmission power value according to a difference between the power sum and the receiving power value.