The SS springs are going to compress slightly more on the wagon, but they will fit. The SS springs are about one inch drop from a stock heigth. The rears may be a little more. If you want something in the middle for the front, you could cut about a half coil off of the front SS springs to get the front a little lower in comparison to the rears. The half coil will give you about 1 inch more drop than the stock SS springs (you can not cut the rears). You should check your camber after the mod. It will go positive from where you are now. If you are at 00 degrees camber now, you should add about .060 shims to all four points. If you are running a large amount of negative camber, you will have less, but may still have to take shims out of the stacks. If you have never changed the shim stacks, you should remove .120 thickness from each stack at 2 inches of drop.
I have a set of 2 inch drop springs all around, and they were for a sedan. I also have drop spindles , and I put a spacer in the front to give me a little more ground clearance, because I had the same problem you do with a 4 inch drop. It now has a nice rake, and clears almost everything.