Well, the spring prop is no longer a problem.
I looked at the geometry, and it was clear that a lot of thought went into it. The prop swings flat as the lid closes, and it retreats from the luggage space.
A spring was a less than ideal solution, but was all the engineer had available 45 years ago. That extension spring geometry in the prop rod was the best they could do - but it put a lot of force on things when closed to do the job open.
After looking at the hook closely, I could see why it almost took your head off:
The sheetmetal was sawing the hook in half!
Obviously a nitrogen charged prop is the answer, and I get to keep the OEM geometry. I used a ball joint to replace the hook, and machined up a spacer to keep the geometry the same. The deck lid has a nice formed area for the hook, and you can get to the back to hold the nut. The spacer spreads the load on the sheetmetal, so it should live a long time:
I made an adapter to use the OEM hook on the lower part, rather than fabricate a new hook. The lower hook pivots the opposite direction, and showed no signs of dangerous wear. The prop puts less stress on things in the closed position than the 45 year old spring did, but because of the linear nature of the nitrogen cylinder it has plenty of force to hold the lid open.
Thanks to everybody that helped here. This little cars is full of "different" for me. I hate to modify anything too much, and tend to stash anything I remove - I consider myself the "current" owner. The "next guy" may actually want the original parts.
B.
