stance correction

[76bonanza]

In an earlier post I told about how the rear of my truck one side sits about 3/4 inch lower than the other after looking and measuring. Looks like it is the coil springs one is just not compressing as much as the other. Two questions,
one how can I tell how low my truck is from stock?

Two looking for ways to correct the coils with out replaceing them what about those coil sprig adjusters?(little clamps and bolt you can use to spread or compress your coil springs?) any other ideas?

Thanks for your help