Thanks for your response.
Naturally, I'd have to go into the PIn Planner first to create the CSV. I don't consider the resultant CSV particularly easy to hand edit later, either. However, that is an option.
Perhaps I could clarify what I'm after. I'd like to be able to create a file of some format (we'll call it a text file for simplicity but it could take any format) that can be added as a source file under the Quartus project that is then read EVERY time the project opens or an Analysis/compilation and Fit is executed.
Similar to an SDC file that contains the timing constraints but this time with placement and other physical constraints (drive strength, slew, IO standard, etc.).
As I wrote previously, I tried to use TCL commands in a secondary QSF file but this didn't quite have the effect that I wanted (e.g. having to import it and not having all constraints imported correctly).