Is it possible to edit Spec editor material assignment per individual component type ? See images below:
I'd like to work smarter if there is a way, thanks.

This is possible, you need to rightclick on the components and then create a new material assignment setup.

You can then manage material per size and per component if needed.

Is this how you assign material description changes on new projects?

I create a new spec every few weeks and want to be smart about it. Typically Forgings, Castings, Wrought Fittings, and Pipe will each have the same descriptions regardless of the description.

I would have to change my template .prj to read the new descriptions in the "SCHEDULE & MATERIAL" to not just read the "USE SPECIFICATION MATERIAL" but each new "SETUP" section for all components? But then each next job I would only change the material as shown above?

Or is this a six of one, half dozen of another situation?

I am not sure I am folliwing you 100%, but you can accomplish updates to the long descriptions based on different material assignments with the relevant long description schema.