Rear spring height?
 

When I bought my 2015 JKU it had a lift and 315 70 r17 tires on it. The lift kit was spacers with stock springs. When I added my front bumper and winch the front sagged a bunch so I bought Rubicon Express re 1370 2.5 inch front springs to get rid of the sag and it levelled out nicely. I'm about to install some axles out of a rubicon 392 x so I figured I should replace my rears while I'm at it. What size rear springs should I look at? I looked for some re 1375 springs but the places I looked were sold out. The research I did told me these were the rears that match the front. Thanks