Where do the 2019 structural assembles save to?
How may I save an assembly from one SPRJ to another?

I think it saves the SPRJ but when you open I never see hand rails, grating, or other assemblies I have saved. The reason I ask is if I make a client specific SPRJ per project and later have another customer with similar assemblies I would like to be able to import the template (like you could import a user shape from one PRJ to another)