Hybrid metal-halide perovskite (PVSK) thin films have recently demonstrated exciting potential as candidates for broadband luminescent solar concentrators (LSCs). Here, we examine the correlation between film thickness, lead halide sources in the precursors, and film morphology, with the optical efficiency of planar PVSK LSCs with a view to optimizing device performance. After synthesizing and testing sixteen different types of PVSK samples, we report a maximum optical efficiency of 34.7% in CH3NH3PbI3 LSC made with Pb(Ac)(2) precursor, and with optimal thickness in the 150-300 nm range. Using 3D Monte Carlo simulations that incorporate experimental results, we accurately estimate self-absorption and surface losses, and most importantly, demonstrate the possibility of scaling these LSCs up to almost 100 cm, thereby providing a route toward optimizing thin film PVSK materials for these and other optoelectronic and photovoltaic applications.