Like everyone else says. You do not have a problem with the fronts.
You need to back off the adjusters on each rear brake. The little wheel. Free it up with WD40 and fiddle with it either way and you will see which way is "backing off". All it does is moves the shoes further towards the drum or away from the drum.
A new "spring kit" is a good idea and they are fairly cheap. Usually you need a special tool and only do one wheel at a time because you will need a wheel for reference. Although, you might not want to get into all that if it is not necessary.
Generally speaking, I find most cars with drum brakes on the rear are not even contacting so the vehicle is pretty well just stopping on the front disc/rotors.