Controlling the nanoscale interactions of colloidal building blocks is a key step for the transition from single nanoparticles to tailor-made, architected morphologies and their further integration into functional materials. Solvent evaporation-induced self-assembly within emulsion droplets emerges as a fast, versatile, and low-cost approach to obtain spherical, complex structures, such as supraparticles. Nevertheless, some process-structure relationships able to describe the effects of emulsion conditions on the synthesis outcomes still remain to be understood. Here, we explore the effect of different physicochemical parameters of emulsion-templated self-assembly (ETSA) on supraparticles' formation. Supraparticle size, size dispersity, microporosity, and sample homogeneity are rationalized based on the used surfactant formulation, stabilization mechanism, and viscosity of the emulsion. We further demonstrate the significance of the parameters found by optimizing a transferable, large-scale (gram-size) ETSA setup for the controlled synthesis of spherical supraparticles in a range of defined sizes (from 0.1-10 μm). Ultimately, our results provide new key synthetic parameters able to control the process, promoting the development of supraparticle-based, functional nanomaterials for a wide range of applications.