Axle skew

[totta Crolla]

Yes Jondee it's interesting you mention the Panhard Rod and lowering, when I removed mine I drew the arc that it took on the floor and at no point over a sixty degree radius did it change by more than 10mm. Of course that could be 20mm difference side to side if lowering the car makes the rod completely parallel to the axle.
I want to get the axle dead centre so that I can adjust the toe angle using the back wheels as a reference.
You also mention rack centreing and I think it is extremely important on an AE86 just a few millimetres out and I found you can start to introduce bad bumpsteer.
To find the rack centre I removed the rubber bellows each end of the rack and measured the protrusion of the actual rack from the housing to the point where it joins the track rod, on my car this is 83.75mm each side. I don't have facilities to lock the steering at this point but I stuck some masking tape on the steering wheel, marked it with a line and made a pointer from the dash to look at it. I then had the alignment done.