Came across this in a quick search for Alex on the Agena Primary Propulsion System. It’s the July 1964 Lockheed report to NASA. Seems pretty detailed on first glance. The Forward (Page iii) says:
This Propulsion Subsystem Engineering Analysis Report is produced by Lockheed Missiles and Space Company for the National Aeronautics and Space Agency and Air Force and is prepared under authority of Paragraph Z.Z.Z, Contract AF-04(695)-IZ9. The document describes and presents an analysis of the Propulsion Subsystem for the Gemini-Agena Target Vehicle.
I’ve uploaded the full PDF file for use.