You could try putting some old toyota rear springs in the front. Depending on far forward you moved the front hanger you may be able to run the later model rear springs that are a little longer  I don't really know the measurements or if that would even work but they would be cheap and easy to find. I think they may be 51" long but I could be wrong.

Stock toy rears move the axle forward 2" because they are only 20.5" on the front half where as a stock toyota front spring is 22.5". But you have to add a few leaves to the pack to make them stiff enough to hold up the front of the truck.
 89-95 rears are 51", 80-88 is 48"