That would be me...I was not removing that liner to get to the bolts, I started by just bending out of the way but the passenger side ripped and I thought ..oh well I will just notch it. They can be flipped and I tried it when I did the coils but man it was a pain in the butt and just flipped them back around.
as far as the weight shifting I crossed that same ditch multiple times in both directions, I'm assuming here but wouldn't shift in both directions?
Good catch on the studs being too long for 1.5" spacers I still don't know if I want to put spacers on, it may be just as easy to build a 2" longer panhard bar to shift the rear end back over....or it could just be worn out bushings.
I'd look for slack or worn bushings or even damage to the bar, it's cheap to replace. But also take a good look at the upper and lower control arms / links. Make sure those mounts / tabs aren't bent. I found the lower arms to be pretty flimsy and went with the Spohn boxed lowers (but haven't yet put them to any significant test yet.
You can do a simple plumb bob test from your frame rails to the axle tube to gauge if your axle is actually shifted over, sitting at rest on level ground. I'll be installing my new rear brake rotors Sunday morning, I can do / take some comparative measurements while I've got things apart, if that would be useful to you.
if anything, at full extension the panhard would contribute to the axle shifting towards the passenger side of the vehicle, if I understand it correctly. I've never really examined how that device is supposed to be helping. I mean it's there to control lateral shifting in 'normal' driving, but at the extreme range it would seem to be doing the opposite.
That pic of the rub marks across the shock bolt, did the bolt tip tear up the inner sidewall of your driver rear tire? That to me would seem to comport with the axle shifting rightward at greater extension due to the geometry of the panhard's swing. Not bent or damaged, but rather that things moved according to the geometry of the design.
I think spacers or negative offset rims would avoid a repeat. I don't think you can just stick a long bar in there to shove the axle over. I mean it would work for a little while, but if something else is really bent it would likely result in the panhard or its mounts failing.
/come to think of it with my 2" rear coil spacers, my axle is probably already offset a hair to the right. We shall see.