Measurements on single-molecule junctions have shown that the conductance of the junctions fluctuates strongly, due to a lack of control of their atomistic structure. In GNP assemblies, several interfaces with many cross-linking ligands contribute to the total conductance. Hence, each conductance measurement in GNP assemblies is automatically averaged over several different interface geometries and ligand arrangements. In our charge transport calculations of the sandwich structures, we also obtain an average conductance over 8 ligands. However, our model interfaces are smaller with respect to their leteral extension than in experiments, and thereby the number of cross-linking ligands is smaller than in GNP assemblies. Additionally, we only consider one interface instead of several ones, and the calculations for the sake of computational feasibility lack time averaging: Charge transport calculations are computationally costly, so as a compromise we averaged the conductance over 10 lowest-energy structures at their preferred surface-to-surface distance for each ligand.