1966 Barracuda FormulaS 6 Leaf spring ride height

Hi,
have no experience with leaf springs. But my fish with wheels on floor and empty has straight leafs. I would say that they are the factory ones. Mybe repaired or restored in the past.
Do i need new one?
What was the factory ride height in the rear? And how to measure them? Could only find for the front a factory height in the service manual.
If i need to buy new one want to order the right ones. I like the lower ones for better curving.
Does someone know the right height. No company could answere my question like hotchkis, mancini, espo,....

My wheels are 15"

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