This paper analyzes how to improve the performance of luminescent solar concentrators based on dye-doped POFs stacked in layers by adjusting the geometric distances between them and choosing appropriate dyes. Improvements in the external photon efficiency greater than 10% could be achieved in this way. These improvements complement other reported ones, including a significant boost in output power when a layer of 10 POFs is used instead of a single POF, far exceeding the tenfold increase in the number of fibers, or an additional large enhancement by adding just one more layer. Our study’s results are related to the degree of matching between the spectral absorption band of the dye used in each layer and the incident power spectrum that reaches the layer. This study focuses on the promising dyes Lumogen Red and Lumogen Yellow, using Monte Carlo simulations and experimental results. It opens the door to new analyses using stacked polymer fibers with improved light-trapping properties.