Unless you heat treat them to make them spring steel, they will not hold the door open. Not all steel can be heat treated to become a spring, especially mild steel. I am guessing that you started with mild steel given how you were able to form this intricate part with relative ease.
You need to start with low alloy, medium to high carbon (0.7-1.0) steel, commonly referred to as "spring steel."
To form spring steel into the desired shape, you need to heat it red hot, make all of your bends, then quench it in oil to restore it to spring steel.
One interesting note about the difference between the '47 doors and the later models is that the '47 doors open further than the later models. There is a bar in the later models which restricts them from opening as far as the '47 doors.
I am surmising that the extra bends in the '47 springs had more tension in them to account for the extra distance which the door travels.
One thing you could do to be able to use later model springs in a '47 door hinge, would be to weld a bar just like what's in the later model hinges to restrict the door from opening too far, so that the springs will stay in place.

1952 5-window - return to "as built" condition | 1950 3100 with a 235 and a T-5 transmission