Update. Several months after I had hoped to do this, I finally got around to installing Karsten’s spring and my shifter gate for the 1-2 gears, copied more or less from the Seine Systems gates.
So now I have a 915 with gates on 1-2 and no tension on the selector mechanism in the gearbox. Best of all worlds.
You can read about the instal in my thread on the Early S forum.
https://www.early911sregistry.org/forums/showthread.php?155077-Converting-to-a-gated-shifter&p=1071850#post1071850