My suggestion would be to modify the code of a local restriction block, and move the Discharge Coefficient (Cd) from "parameter" section into "inputs" section. Save it as a custom component or build your own library from there.
https://www.mathworks.com/help/physmod/simscape/creating-custom-components.html
https://www.mathworks.com/help/physmod/simscape/simscape-file-deployment.html