Though mechanical properties of amorphous materials are commonly studied by molecular simulation, modeling the optical response of nanoparticle assemblies with complex structural features involving large numbers of particles has been computationally intractable. Accordingly, how local structuring affects resonant light-matter interactions in disordered plasmonic materials such as colloidal gels with strong LSPR coupling remains poorly understood. We recently introduced a highly efficient mutual polarization method (MPM) capable of rapidly computing optical properties for arbitrary configurations of thousands of spherical nanoparticles with up to triply-periodic boundary conditions, including mixtures of colloids with different dielectric functions. Here, we use this method together with configurations generated from an experimentally-informed coarse-grained model to explore via simulation how linking molecules can be selected to deliberately modify structure in colloidal gels for desired optical and mechanical properties (Fig. ). Our simulation results establish linker molecular weight distribution as a powerful tool for designing plasmonic linker gels. As previously hypothesized, we found that optical extinction spectra can be tuned largely independent of gel elastic properties by employing different blends of short and long linkers with fixed average molecular weight. Short linkers strongly constrain the distance between nanoparticle surfaces they connect, creating small interparticle gaps. Increasing the proportion of these gaps strengthens LSPR coupling in the network, leading to high near-field enhancement and broadening the optical extinction spectra. On the other hand, as in polymer networks, the elastic moduli and elongation behavior of the resulting nanoparticle networks depend on average linker length, but are otherwise insensitive to the details of the linker-size distribution. Together, this modeling predicts that linker composition provides a convenient experimental handle for modulating the optical response of gels without sacrificing key aspects of their mechanical properties.