Here is a little lesson on how to use the free lengths and spring rates.
The rate is how much weight is required to compress the spring one inch.
The free length is the uncompressed length of the spring. There is no vehicle weight on it.
Ride height is the length of the spring with the vehicle's weight on it.
The solid height is when the spring is at full compression and is a solid mass. This is rarely a concern except for dumb spring designs like Metalcloak that require additional bump stop to prevent the springs from going solid.
The ride heights of the stock TJ are about 12" front and 8" rear. This is measuring from the top of the spring to the bottom of the spring. This measurement does not include the isolators or spring spacers.
Sprung weight is the weight of the vehicle being supported by the spring. This does not include the axles, tires, etc. Technically the sprung weight includes half the weight of the springs shocks, control arms, etc. But most of us don't need to get that detailed.
Let's say a front spring has a rate of 100lbs per inch and a free length of 25".
If the spring has a rate of 100lbs and the corner sprung weight of the vehicle compresses the spring 9". That means the corner weight of the vehicle is about 900lbs. And the ride height of the spring will be 16". And because we know a stock front TJ spring has a 12" ride height, we can figure out that this example spring provides a 4" lift over stock.
If your Jeep has one of the springs listed above, you can closely calculate the sprung weights of your Jeep and then you can use that calculated sprung weight to predict what another spring will do to your Jeep.