John, I have 15x8 -4 with 10mm longer lcas, which puts the wheel roughly where your fronts sit.
Fronts are easy to roll/pull, with a 195/50 most of the tyre is inside the guard. I have stretched the guard while retaining the 'square' edge, and the paint (at least on the outer) is fine.
Looks like the pano rear will be easier than sedan, as sedans have a seam down the center, and as you stretch the guard the spot welds pull out! But really I think you should get new arches welded on the rear to fit those wheels, or someone talented with an oxy
blzbub: Love that wagon hey! He has a thread on 86dc if you havent seen it yet