Building on the new droplet drying framework developed by the authors in their previous papers, this paper develops physically motivated criteria for dynamically deciding the appropriate structural sub-model to use at each stage of the drying process. Such criteria create a spatially resolved mechanistic droplet drying model which, for the first time, is capable of simulating multiple dried-particle morphologies based on evolving droplet composition and drying conditions. The new criteria are used in conjunction with the previously described model framework to simulate colloidal silica droplets, investigating the relationship between suspended particle size and dried-particle morphology.