What are the current best practices for Simulink parameters that will be called from a Matlab function?

There are lots of ways of passing parameters to a Simulink model from a Matlab function (e.g. if you are running the model using sim() within an optimiation function). E.g. using simset('SrcWorkspace','current'), or assignin('base',...) and many others. While these all work, none of them seem like what I'd like of as good practice.

My question is what people recommend as best coding practice from the points of view of code/model readability, mainainability, reuse, etc.