While I am guilty liking a lot of bar , that is a LOT
of bar! !
When doing your front to rear bar ' figgerin" remember to must take into consideration tubular vs solid
While millions of cars use the strap to lower arms type rear bar, it is less than optimal from a design standpoint.
One thing I noticed in my case , with poly type rear arms , the susp would seem to go into bind as it rolled which will spike outside loading.
I since changed to a bearing type arm and that tamed the , at the limit, oversteer sensation.
I "only " have a 1.25 solid rear bar and 1.25 solid front but the front is the short arm "F" bar repositioned back so it "acts" like a large "B" bar.
On the street, I am happy, but will note even with the front disconnected on the way to the drags, it is not evil oversteer.
The wagon is tail heavy and add the pendulum effect of the tail gate WAY back there, part for part is going to be more tail happy than the sedan.
While I live in a road racing environment, I have not road coarsed my wagon and must defer to people here with experience for actual "B" body track use
On the street, if you are keeping that rear bar, I think you are going to need some more front bar.
My gut would look at the Spohn if it is a true "B" body arm length
Take the above for what it is, an opinion