Trying to determine lift height

Just an update, this is the kind of BS y'all were talking about when you said people do weird shit to TJs. It appears that both rear springs were cut down from a 4" spring to a 2" spring. 🤷🤷🤷. I purchased 3" BDS springs, put them in last night and it leveled to whole jeep right out. It may have a little bit of a rake but I'm buying the matching fronts to make it even.

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I'd measure the rear springs unloaded to get a true baseline, then pick new ones rated for your heavy bumper and spare.

If you are going to go by the free length of the coil, then you need to factor in the spring rate.