How can I get a list of all user-settable Simulink model settings that are evaluated?

How can I get a list of all user-settable Simulink model settings that are evaluated (strings that are executed as code to get the property value)?

I want this as part of my effort to programmatically find all base workspace variable references in the configuration settings of my Simulink model. For example, the property 'ExternalInput' references a Simulink Dataset in my base workspace. As far as this question is concerned, it would be just as well if it didn't reference that Dataset; what I really want is a list of all the model properties that could reference a variable.

So far, I know I can get all the model (let's call it my_model) properties with:

h = get_param(my_model, 'Handle');
properties = get(h);
allowed = set(h);

From these, I can search for properties whose values are strings and allowed to be anything. ( set returns an empty cell for these.)

fields = intersect(filenames(properties), fieldnames(allowed));
fields = fields(cellfun(@(f) ischar(properties.(f)) & is empty(allowed.(f)), fields));

But this still includes properties such as 'Name' and 'ToolBar' that are never evaluated and so don't matter in this context.