Use the thickness of a material as a numeric variable. This variable would then always be used by the deck inset. For example, assume a 2" high bottom rail. For deck inset, the value would be 2 - MT, where MT equals material thickness. Now, if you get a batch of material that is thinner or thicker then the last batch you used (which is always the case), you can just change the material thickness in the material editor once instead of changing the deck inset on each of the cabinets in your batch or your room layout.
If I may touch on this subject again. As Eddie stated about the deck plaisment.The left and right stile length should be determined by the toe kick height and Therefore the bottom edge of the bottom rail should be plaised at the bottom of the stiles then the top of the deck should be at the top of the bottom rail then the user could apply the deck float



